While there are plenty of legitimate models with millions of followers on Instagram (IG), there are also a bevy of “Insta-models" whose glamorous lives sources tell FOX411 are provided not by actual modeling work, but by Johns from whom they solicit sex by using the popular social media app.

Now sites like The Dirty, Tag Your Sponsor, and Tag The Sponsor are being used to out women allegedly using Instagram to secure sex clients.

Nik Richie, founder of The Dirty.com, told FOX411 he began to see call girls using the social media app around three years ago.
“I started getting swarms of submissions to TheDirty.com from guys debunking female modeling careers because these women would constantly be flashing cash, private jet flights and exotic trips, but they had no jobs,” Richie told FOX411. “Their IG photos flaunted the ultimate lifestyle only afforded by rich men.”

The blogger, whose site broke the Sydney Leathers and Anthony Weiner sexting scandal story, said he can tell a legitimate working model from an IG call girl based on their app activity.

“For some reason these women need to brag about their façade; posting pictures on their IG of $25,000 dollar purses, red bottom shoes, cash and of course the selfies from a yacht in the South of France or Dubai,” Richie said. “100 percent of their IG postings are fake set up situations to lure more men to ‘like’ their pictures.”

A modeling industry insider explained that these women use social media as a way to attract future clients with seductive photos, noting there is no way selfies can translate into enough money to maintain the luxurious lifestyle they document.

“The sexy photos and videos are always giveaways to lure people in. The vast majority of these women aren’t making money from modeling,” the source said. “Going to a beach in a bikini isn’t a paying job. You get no income for having 30,000 followers on IG. That $1/1K followers [rate] is pretty much the standard for any kind of endorsement deals, should a model secure one.”

Which means sending a pic of oneself modeling a product to 30,000 followers would typically net a model with an endorsement deal around $300.

The site Tag The Sponsor refers to such women as “sponsorettes” whose lifestyle is provided by a “sponsor,” their term for John. 
A source added that while Instagram is the latest frontier for prostitution, “the buying market hasn’t changed. This is just a recent avenue for the oldest profession.”

A John who asked we not use his name told FOX411 he solicits escorts on Instagram by looking for models who pose alone on yachts, private jets, exotic vacations, and wear luxury items, as well as those who post personal email addresses using domains like Yahoo! or Gmail rather than listing a legitimate modeling agency like Elite or Ford.

“I email her first saying she’s beautiful. Then, I ask how much her time is worth. How much would lunch cost me… $500?” he said. “We go back and forth until we reach an agreement. If she’s meets me in person, then I know she’s willing to do anything for money.”

The John said that IG prostitutes can make a range of money for sexual favors starting at around $500 per hour, and that seasoned escorts can bank over $10,000 for an overnight stay.

Of course Instagram does not approve of such behavior from the Johns or the women, stating in their Terms of Use: “You may not use the Service for any illegal or unauthorized purpose. You agree to comply with all laws, rules and regulations (for example, federal, state, local and provincial) applicable to your use of the Service and your Content (defined below), including but not limited to, copyright laws.”

We reached out to Instagram to see if anyone has been removed from the service for using it to promote prostitution but did not hear back.

As for a woman who might be outed on sites like The Dirty and Tag Your Sponsor, Richie said the publicity can actually help increase their business.

“These women panic at first, threatening legal action against TheDirty.com, but what is better than money is fame," he said. "They instantly become Insta-famous and a sea of men reach out to them ready to open their wallets for sex.”

FOX411 reached out to Tag Your Sponsor and Tag The Sponsor but did not receive comment.

Fox News.com Reporter and FOX411 host Diana Falzone covers celebrity news and interviews some of today's top celebrities and newsmakers.  You can follow her on Twitter @dianafalzone.