Want to throw your kid a Sweet 16 she’ll never forget?

For a cool $250,000, Usher will turn up and sing “Happy Birthday,” Jeremy Piven will carry out the dessert tray for $50,000 and Dennis Rodman will DJ at the party for the bargain fee of $20,000.

Increasingly, all kinds of celebrities are available for hire — at every event imaginable.

While it was reported this week that Jennifer Lopez has earned $9 million performing for tyrants around the world over the past two years, a growing number of celebs are making big bucks entertaining regular fans at private soirees.

“People love celebrities, and every star has a price,” says New York-based celebrity booker Matt Altman, owner of Headline Booking Group, which connects celebrities with people hoping to brighten their bashes with star power.

Not all stars are willing to perform for despots, but many will turn up at your party if you’re able to shell out. Want the Piano Man? Or to be sung “Margaritaville” by the man who wrote the song? Billy Joel or Jimmy Buffett will do it — as long as you can pay more than a million dollars, says Steve Einzig, owner of Manhattan-based BookingEntertainment.com.

In the past five years, the niche entertainment business of booking celebrities for private parties has grown, as elite New Yorkers compete to throw bigger, better, splashier events for their children and other loved ones.

Usually stars don’t brag about their freelance work, preferring to keep any moonlighting hush-hush. But, with social media, details can get out: In June, when Nicki Minaj was hired to perform at a New York bar mitzvah, she later tweeted: “Just left the Bar Mitzvah. Bout to shut NY downnnnn.”

Along with weddings and bar mitzvahs, one-on-one meetings are available, too.

In 2009, an unidentified Iraqi businessman paid about $20,000 for his daughter to meet her favorite pop star, Miley Cyrus, backstage at a concert, Einzig says.

The lucky fan attended the sound check, hung out with her idol and sat front-row for the concert.

The kindhearted Cyrus donated her fee to charity, Einzig says. (Cyrus’ rep says the star has never worked with Einzig and the star only does paid meetings for charity auctions.)

But that was small fry. Kanye and Jay-Z scored $3 million each to perform at a Sweet 16 for the daughter of an Arab billionaire in 2011, according to MediaTakeOut.com.

That same year, Kanye turned down former NBC honcho Jeff Zucker when he offered a measly $1 million to play at his son’s lavish Four Seasons bar mitzvah, according to Page Six. Zucker settled for the more modestly priced Drake.

In 2009, Usher made his quarter-million fee when he surprised a birthday girl by emerging from a kitchen at a London club while singing “Happy Birthday,” Einzig says. Piven, meanwhile, made $50,000 in 2006 for appearing at a San Francisco party for an hour, bearing confectionary treats, according to Mike Esterman, who owns DC-based celeb-booking agency Esterman.com.

But it’s not just the super-rich who can book a star for their party — anyone can do it, especially if they’re eager to hang with a reality TV star.

Many Bravo celebs go for less than $1,000 for personal appearances; Erica Gimbel from “Princesses: Long Island” has a low, low rate of $500, reveals Esterman.

One-hit wonders can also keep the checks coming long after they fall from iTunes rotation, but they’re not as cheap as you might think.

Remember Iyaz? Probably not, but you may recall his 2010 song of the summer, “Replay.” The young singer pocketed $30,000 for each of back-to-back bar mitzvahs — one in Manhattan, one on Long Island — according to Esterman.

The legendary Beach Boys, less surprisingly, are very much in demand.

Chey Reynolds, as Verizon’s group manager of marketing communications, wanted to add a little wow to a Vegas conference in April 2010. She Googled “celebrity appearances” and found Einzig, who suggested the legendary ’60s pop band.

After booking them, however, she worried they wouldn’t be hip enough, so Einzig threw in John Stamos as a surprise guest. (Einzig wouldn’t reveal the fee.)

“Everyone was blown away. They were as impressed as hell with the Beach Boys. When Stamos came out, it brought the whole thing together, he was phenomenal,” says Reynolds, who has also hired Kool and the Gang for a disco party and Buddy Guy for another bash.

“There’s a little bit of a one-upmanship with trade shows and conferences,” she says. “You see it with the tech companies. It’s amazing who they’ll bring in for a night of entertainment.”

According to Einzig, the formula for a star’s asking price is their level of wealth plus their level of fame, in addition to the logistics of the event — like how far the performer will need to travel. (All travel costs and accommodations are paid for by the buyer on top of the asking price.)

Of Jimmy Buffett, Einzig says: “You’ve got to pay a lot to get him off his yacht or wherever he’s hanging out these days.”

But not all stars will sell out for some shell-out, and The Boss is one of them.

“Bruce Springsteen is pretty much the only one who will not do corporate events or private parties,” Einzig says.

Springsteen turned down $1 million to perform at a bat mitzvah at the Rainbow Room in 2005, refusing even when Einzig offered to donate the fee to charity, the booker claims.

It’s a good thing he skipped it.

The event was for the daughter of David Brooks, the former CEO of the leading supplier of body armor to US soldiers in Iraq, who was charged with looting the company to bankroll his lavish lifestyle, including the $10 million bat mitzvah.

Aerosmith, 50 Cent, Tom Petty, Kenny G and the Eagles did perform at the event.

As for the ethics of performing for dictators and corrupt businessmen, one booker says it’s not up to him.

“The decision to perform would be up to the artists themselves,” says Esterman. “I don’t play God. I’d say, ‘This is our offer on our table, it’s within the budget.’ Ethics are up to them, everybody is different, they’ve all done controversial things, they have their own sets of standards, how would I know?”

But not all bookings end in controversy. And some can even lead to a star’s personal happiness.

Singer Meat Loaf discovered just that when he was booked to perform at a victory party in Barbados for a big shot’s racehorse in 2002.

“[Meat Loaf] was just getting separated from his wife,” Einzig explains. “He looked into the audience when he was performing and saw a woman who caught his eye, and he talked to her that night, came back the following week to see her again and married her.”

kstorey@nypost.com