[mobile answer, so I can’t upload a photo!]
That should be a pretty cheaty thing to do. I don’t know any specific laws for the situation, as my country doesn’t allow slave contracts, but there are probably regulations surrounding it.
Also, if you’re the kind of person who tries to cheat other people after you’ve made a deal with them, you’ll get a bad reputation. In any modern country, you’re selling your current life, and being given something in return. It’s dishonest to try and short change whoever is on the other side of the exchange.