Has your wife ever used her body to pay an outstanding account???

Sort of yes. The idea was not to save money or rent but basically being a hotwife, she is also a submissive pet for dominating men. N around 2.5 years back we had a very dominating man who after initial fun made the proposal to let us move in with him so he can cuck me and use my wife daily as he pleased at any time.
My wife couldn't say no and I had no saying in it... So eventually we moved in with him and live for 8 months together free of rent or any household expenses besides paying for it all through my wife body and our humiliation 24*7.
 
We stayed at an hotel a few years ago and Becky had sex with the owner to pay the bill. We were happy to pay, but he suggested it in a very unsubtle way after our first night. He just came out with it, "if you want to fuck me, I won't charge you a penny for your stay".

Did she WANT to fuck him...? No, not at all but she thought "it's only a cock, what the hell, he's overweight and ugly but I'm not looking to marry him"

He came up to our room after breakfast, stripped her naked and fucked her bare. He dropped his trousers to his knees, bent her over a chair ( she was so glad he took her from behind and she didn't actually have to watch ) he huffed and puffed and didn't last more than a few minutes before he came over her tits, then told her suck him clean. He barely said anything and the whole episode was as unsexy as it can get.

She felt very degraded and thoroughly used but at the same time, the whole seediness was actually very empowering for her.

Would she do it again...?

Yes, probably...!