I had a friend who once married a chick he knew as a friend so she could get citizenship.

I teased him about it forever. He did it for free and never even got any nookie out of the deal.

If I remember correctly, they had to stay in contact for like 5 years. Their mail had to go to the same address. I think the last year they had to live together.

If 5-10k is worth dealing with it for 5 years, then go for it.