In today’s lousy economy, men can take comfort in knowing that there is one sought-after good that is becoming steadily more affordable: sex.

Women are jumping into the sack faster and with fewer expectations about long-term commitments than ever, effectively discounting the “price” of sex to a record low, according to social psychologists.

More than 25% of young women report giving it up within the first week of dating. While researchers don’t have a baseline to compare it to, interviews they have conducted lead them to believe this is higher than before, which increases the pressure on other women and changes the expectations of men.

“The price of sex is about how much one party has to do in order to entice the other into being sexual,” said Kathleen Vohs, of the University of Minnesota, who has authored several papers on “sexual economics.” “It might mean buying her a drink or an engagement ring. These behaviors vary in how costly they are to the man, and that is how we quantify the price of sex.”

By boiling dating down to an economic model, researchers have found that men are literally getting lots of bang for their buck. Women, meanwhile, are getting very little tat for their . . . well, you get the idea.

Sex is so cheap that researchers found a full 30% of young men’s sexual relationships involve no romance at all — no wooing, dating, goofy text messaging. Nothing. Just sex.

Men want sex more than women do. It’s a fact that sounds sexist and outdated. But it is a fact all the same — one that women used for centuries to keep the price of sex high (if you liked it back in the day, you really had to put a ring on it). With gender equality, the Pill and the advent of Internet porn, women’s control of the meet market has been butchered.

As a result, says Mark Regnerus, a sociologist at the University of Texas at Austin, men are “quicker to have sex in our relationships these days, slower to commitment and just plain pickier.”

The issue is partly one of supply and demand, and it begins at US colleges, where 57% of students are women. With such an imbalanced sex ratio, women are using hookups to compete with other women for men’s affections. Once they get out of school, the pool of successful, educated men also is imbalanced, and the bed-hopping continues.

Regnerus likens the price of sex to the housing market. Too many foreclosures in one community, and the price of neighboring homes start to plummet. This is why single women in New York sometimes feel as though sex on the first date is a given: According to the market, it is.

“Every sex act is part of a ‘pricing’ of sex for subsequent relationships,” Regnerus said. “If sex has been very easy to get for a particular young man for many years and over the course of multiple relationships, what would eventually prompt him to pay a lot for it in the future — that is, committing to marry?”

Did you answer, “Love”? You’re adorable.

“Sexual strategies for making men ‘fall in love’ typically backfire, because men don’t often work like that,” Regnerus says.

It’s little wonder that the percentage of 25- to 34-year-olds who are married has shrunk by an average of 1% each year this past decade — down to 46% now. Single women have been catching on, but those who don’t discount sex say they can’t seem to get anyone to “pay” their higher price.

As with many other markets, outsourcing and technology have affected the price of sex as well.

“If men don’t want to take the time to woo a real woman, they can watch sex acts in high definition with images of women who never say no,” Regnerus says. “If you have a suboptimal date with someone you met online, you’re apt now to log on and see who else is available rather than to have another try at it.”

The poor economy is adding to men’s reluctance to commit. Men worry about not being able to provide for a family and about the economic pitfalls of divorce.

So, what can women do to return the balance of sexual power in their favor? Stop putting out, experts say. If women collectively decided to cross their legs, the price of sex would soar and women would regain control of the market. Like a whoopie cartel.

Women in less egalitarian countries do tend to restrict sex as a means of keeping the cost high. This makes sense when women have no access to education and employment. But in the US, it would take a major cultural movement for women to convince each other to say no to nookie.

“Let’s be realistic: It’s not going to happen here,” Regnerus says. “Women don’t really need men and marriage — economically, socially, and culturally — like they once did. What I hear in interviews with women is plenty of complaining about men or about the dating scene, but their annoyance is seldom directed at other women.”