Getting married for $$$ is not very profitable once you include the costs of divorce.
A much more profitable immigration scam is opening a nursing home (can be as small as 4 beds) and hiring women to be nurses under the
H-1B immigration program. As the business owner, you fill out the paperwork to give them a 3 year work visa. It can be renewed once for an additional 3 years. And then they have to return to their home country so you don't have to deal with them ever again. In reality these girls are working under the table at crap-ass unskilled sweatshop jobs or in backroom kitchens untaxed (or if Hispanic, working in an illegal "grow house"), they pay you for the bed rental for their non-existent relative, and you pay them back the laundered money minus your cut. I'm sure if someone paid you $35k up front lump sum you could include them in your worker list and get them a work visa for a job they'll never show up to the same as the others on your "staff". Nursing homes need people working shifts 24 hours a day, after all.
The H-1B scam also works with fake high tech companies. Every Indian cab driver you talk to is a "Software Contractor at a High Tech Company between jobs." Yeah right. The worst was an Indian landlord
Lakireddy Bali Reddy in Berkeley --he was bringing in
14 year old sex slaves to a fictitious high tech company, all of whom had fake Computer Science Degrees from non-existent universities so they qualified for the H-1B visa program, despite the fact that most of them couldn't even read (The H-1B program oversight is that stupid) . He ran his prostitution ring just fine until
some of them died on the job. Silicon Valley calls these fake high tech companies "paper tigers" --they tout how great their contractors are on paper to look good to immigration, but in reality all their staff are cab drivers and hookers paying the owner under the table to stay on his books. Occasionally a new out-of-town manager will make the mistake of calling up one of these fake companies and actually hiring their know-nothing contractors for a real job. Guaranteed career ending move.
I think immigration fraud is bad, and it's illegal. But if you're thinking about pulling a scam, be aware there's far more profitable, and subject to far less oversight, immigration scams than a fake green card marriage that you could only run with one woman at a time.