People who live with parents

So I live with my parents (not my real parents adoptive) and I have to pay them £50 a week so £200 a month which is 278 dollars for friends across the pond. But I can’t help but feel old I’m getting ripped off I think I’m being charged a lot more than I should bare in mind i have to buy all my own food pay for anything I need, our baths and showed are limited not allowed more than 2 a week and we’re not allowed to cook or use electricity after a certain time. They tell me I’m paying for living in the house but everything in my room I baught including my own bed floor and even painted all the walls myself with no help. I’ve told them I think I’m being charged to much when I have to pay for things like my own food and they say things like I need to pay them bs k for all the money they spent on me when I’m not even their child they didn’t have to have me I could of been left with no one. I just want to know what everyone else is paying and if you think what I’m paying is fair. I have no problem paying this much if it is a fair price but I just want to make sure because after I pay them the money I only have like £20 left to buy everything I need and a lot of times I have to borrow money because of that