Halloween can be a real scream for your bank account.

Between designer costumes, organic pumpkin patches and pricey haunted houses, celebrating spooky season — especially in NYC — can quickly turn into a financial fright.

But you don’t need to shell out for a haunted attraction to get into skeleton mode this October, since this year, there are dozens of ways to get your treats without any cash-leaking tricks.

From internet-famous dog costume parades and family-friendly fall festivals to elaborate neighborhood decorations that turn an ordinary stroll into a walk through a macabre movie set, The Post rounded up free festivities across the five boroughs that New Yorkers can partake in leading up to All Hallows’ Eve.

Have a howling good time

Forget a clever costume for yourself — it’s time to brainstorm the ruff-est way to dress your dog for trick-or-treating.

Get inspiration from the Tompkins Square Halloween Dog Parade, returning to the East Village on Saturday, Oct. 17. Spectators can watch the costumed canines strut their stuff for free as the parade makes its way south along Avenue B, from East 13th Street to East 7th Street near Tompkins Square Park.

Registration for those hoping to enter their own fluffy fashionista has already filled up, but watching the canine couture strut their stuff won’t cost puppy lovers a penny.

Now in its 36th year, the Tompkins Square Halloween Dog Parade is a full-blown canine costume extravaganza, with pooches sporting everything from NYC-inspired getups to pop-culture-worthy couture. Michael Nagle

Longtime New Yorker Rebeka Getty, 32, says dog costume contests are among her favorite ways to celebrate Halloween.

“I always love the dog costume parades and contests,” the Brooklynite, who runs the popular NYC For Free page, told The Post. “It’s one of my favorite ways to celebrate the season every year without spending money.”

Born from grassroots efforts to create the city’s first official dog run, the beloved East Village tradition is proof that in New York, even the dogs know how to steal the show. Emmy Park

She says the fun continues uptown at Carl Schurz Park, where the Conservancy’s Halloween Howl takes place Sunday, Oct. 18, from 1 to 3 p.m. Visitors can enter the park near East 84th Street and East End Avenue or at East 86th Street and East End Avenue.

The annual event draws more than 200 creatively costumed pups, all hoping to impress a panel of fashion-industry judges whose identities remain under wraps — for now.

The annual Halloween Howl draws more than 200 creatively costumed pups with a canine catwalk where four-legged fashionistas compete for bragging rights before a panel of “blue-chip fashion industry” judges. Carl Schurz Park Conservancy

Yorkville resident Ally Gibson, 36, also calls the gathering one of her “favorite local autumn activities,” praising the “adorable dogs and their equally enthusiastic owners.”

The park’s Harvest Fest also takes place that afternoon, with a pumpkin patch on Gracie Oval, arts and crafts, a Spooky Trail and a family concert — making it easy to turn a free dog-watching excursion into an afternoon of fall fun.

For Queens resident Lea Chen, 28, the appeal of Halloween dog meet-ups goes beyond the costumes — they can make for a memorable date, too.

Her love of the gatherings dates back to a Halloween event at the South Street Seaport, where she watched costumed pups while on a date with her now-partner, years before she had a dog of her own.

Some pups serve up truly iconic costumes, like this pug dressed as Audrey II, the man-eating plant also known as “Twoey” from the horror-comedy musical and film “Little Shop of Horrors.” Michael Nagle

“I still remember seeing one dog dressed as ‘Taco Bella’ as a play on Taco Bell, and it totally made my day,” she told The Post.

Now that she has a pup of her own, Chen, known as an NYC freebies guru, says these free gatherings are her favorite way to kick off October — and “typically cost only the subway fare” unless you walk to them.

Take a spooky stroll

Sometimes, the best and eeriest entertainment is right outside someone else’s front door.

From the west side of Manhattan to lower Brooklyn, Gothamites transform brownstones and apartment stoops with pumpkins, skeletons, cobwebs and elaborate Halloween displays.

A self-guided decorations tour lets visitors soak up the spooky scenery without paying admission.

In New York, Halloween decorating is practically a competitive sport — and the brownstone stoop is the city’s stage. Designer Hillary Simon Wallaces is known for her epic set-up on West 82nd Street in Manhattan. Stefano Giovannini

Getty recommends exploring the Upper West Side, Brooklyn Heights, Park Slope and the West Village, where residents go all out with seasonal decorations.

“I love a good Halloween decorations tour. Some apartments, brownstones and buildings decorate every year,” she said, adding that her favorite creepy corners are on the Upper East Side. “You can find more than 15 spooky houses in a 10- to 20-block radius.”

For a more targeted tour, head to West 69th Street between Central Park West and Columbus Avenue, where decorated Upper West Side brownstones turn an ordinary residential block into prime Halloween sightseeing.

Rebeka Getty loves strolling past elaborately decorated brownstones and stoops on Manhattan’s Upper West Side and in Brooklyn Heights and the West Village.

Across the river, head to Cobble Hill’s Congress Street, between Court and Columbia streets, where historic brownstones and seasonal decorations make for a picturesque walk.

Nearby, Clinton Street and the residential blocks between Court and Hoyt streets offer more opportunities to spot pumpkins, cobwebs and other neighborhood-made frights.

In Brooklyn Heights, make a beeline for Garden Place, between Joralemon and State streets, where residents go all out for Halloween, then swing by Grace Court Alley, off Hicks Street, to see its famously festive pumpkin displays.

The Larussi family’s home on 11th Street in Park Slope is a neighborhood Halloween favorite, drawing kids eager to trick-or-treat there and admire the elaborate decorations in the days leading up to Oct. 31. Stefano Giovannini

A detour along Joralemon Street, between Furman and Hicks streets, rounds out the atmospheric neighborhood walk.

Gibson, a Yorkville resident, recommends “heading out around dusk,” when fading light and glowing jack-o’-lanterns lend an extra dose of Halloween magic to neighborhood streets, including East 87th Street between York Avenue and East End Avenue and East 78th Street between Park and Lexington avenues.

“A stroll through them costs nothing,” she says, adding that leaving around twilight offers the “best light and the most spooky atmosphere.” Bonus points if you bring a hot drink to enjoy as you wander around.

Cheryl and Marcel Van Oonyen are known for their over-the-top annual Halloween displays at 594 11th St., between Prospect Park West and Eighth Avenue. Stefano Giovannini

For a more haunting backdrop, she recommends heading to Brooklyn’s Green-Wood Cemetery at 500 25th St., a historic burial ground that became a 19th-century tourist attraction and helped pave the way for public green spaces like Central Park.

“It’s free to walk the grounds, and the Victorian monuments and skyline views are perfect for a moody autumn afternoon,” she said. 

The lawns are free to explore, but remember: this is a cemetery, not a haunted house. Leave the Ouija board at home, skip the ghost-hunting theatrics and save those “Hocus Pocus” reenactments for your own backyard.

Green-Wood Cemetery is the final resting place of an astonishing roster of famous New Yorkers and cultural icons, from legendary artist Jean-Michel Basquiat to composer-conductor Leonard Bernstein. Paul Martinka

Brooklyn’s Green-Wood Cemetery is a city of the dead in its own right, sprawling across 478 acres to claim the title of New York City’s largest cemetery by land area. Paul Martinka

For a truly gargantuan fall photo op, head to 69 8th Ave. in Park Slope, where resident Charlie Pigott has turned his front stoop into an unofficial pumpkin patch with a monster-sized gourd.

The tradition made headlines last year when Pigott hauled a roughly 1,000-pound pumpkin onto his brownstone using a forklift — proving some New Yorkers take pumpkin spice season very seriously.

The sidewalk spectacle is free to admire, making it a prime spot for a supersized seasonal selfie without the farm admission fee.

For a neighborhood display with a little more bite, head to 21 Jay St. in Tribeca, where an elaborate Halloween installation dubbed “Nightmare on 21 Jay Street” features ghoulish characters that move and speak.

Part of the city’s Trick-or-Streets festivities, the spooky spectacle is open Monday through Thursday from 4 to 10 p.m. and Friday through Sunday from 4 to 11 p.m. through Halloween.

A Halloween block party and inflatable corn maze add to the neighborhood’s creepy takeover, offering an unconventional way to get your thrills without shelling out for a haunted-house ticket.

Reign on your parade

The Village Halloween Parade is one of the city’s signature spooky spectacles, and watching the elaborate procession, with its costume crews and jaw-dropping giant puppets, is free.

This year, the parade falls on Halloween itself — Saturday, Oct. 31 — and marches north along Sixth Avenue from Canal Street to West 15th Street, passing through Greenwich Village.

The Village Halloween Parade is a monster of a street party, drawing more than 2 million spectators and turning 50,000 to 80,000 costumed revelers into a ghoulish procession each year. Paul Martinka

Expect innovative costumes, floats created by Broadway set designers and plenty of creative performances — plus plenty of inspiration for next year’s costume.

Gibson says the ThrillerNYC zombie dancers are a highlight. The group has performed Michael Jackson’s “Thriller” dance in the parade since 2004.

For many New Yorkers, one of the parade’s biggest thrills is watching professional dancers rise from the dead to recreate the iconic zombie choreography from Michael Jackson’s 1983 “Thriller” music video. Paul Martinka

Her advice for spectators: Arrive “extra early” (the parade starts at 7 p.m.) to claim a viewing spot.

Coming from another borough? Don’t overlook the Bronx.

Getty points to Longwood’s own long-running Halloween Parade, which is celebrating more than 40 years as a neighborhood staple. It’s scheduled for Oct. 24 with the theme “Carnival of Nightmares,” followed by a block party at Bill Rainey Park.

Manhattan isn’t the only borough that knows how to put on a Halloween show: The Bronx Halloween Parade has spent more than four decades celebrating local culture with plenty of community spirit and spooky flair. Kiara Terrero

Get batty at a free festival

For families looking for a little more than a neighborhood walk, NYC Parks has a lineup of free Halloween-season events across the boroughs.

Upcoming options include the Halloween Harvest Festival at Socrates Sculpture Park in Astoria on Oct. 31, along with other park-hosted celebrations featuring seasonal activities and opportunities to get creative at 32-01 Vernon Boulevard.

The festival is slated to include pumpkin decorating, art workshops and its own dog costume contest.

From bat-themed fun at Astoria’s Socrates Sculpture Park to waterfront festivities at the South Street Seaport, these free Halloween happenings serve up a mix of spooky surprises, maritime history and family-friendly fun. South Street Seaport Museum

Chen says she is especially intrigued by one decidedly unusual offering: a “Field Guide” session devoted to local bats, where participants can learn about the animals’ role in NYC’s ecosystem and make bat-inspired art.

“I’ve honestly never seen a bat-focused workshop at any other Halloween event in the city, and I’m a total sucker for learning about animals,” she said.

For an autumn escape that feels a world away from the city, hop a ferry to Governors Island for Pumpkin Point, returning to Nolan Park on Oct. 24 and 25. The seasonal gathering features a giant pumpkin patch, arts and crafts, trick-or-treating, ghost tours and performances.

Queens resident Lea Chen loves when fall takes over the city — especially when New Yorkers can hop a ferry to Governors Island and get their pumpkin-patch fix with a skyline view.

Admission to Pumpkin Point is free, but the ferry isn’t necessarily: visitors should check the schedule and fare options before setting off, since transportation costs can turn a supposedly free outing into a less budget-friendly excursion.

Other free park events this season include the Pumpkin Palooza at St. Mary’s Park in the Bronx on Halloween at 450 St. Ann’s Avenue.

For another dose of fall fun, head to the Upper East Side this Sunday, Oct. 18, for the Carl Schurz Park Harvest Festival. The free festivities run from 1 to 3 p.m. at Mayor’s Lawn and Gracie Oval, near East End Avenue and East 88th Street. Carl Schurz Park Conservancy

As Getty stresses, “All the parks in NYC have their own free Halloween events, so there’s no need to travel far to celebrate.”

Big Apple denizens can check NYC Parks’ online calendar for additional Halloween and kids’ fall programming throughout the five boroughs — then plan a howling good October without sending your bank account screaming into the night.