Its difficult, my husband has a low wage and has been out of work a few times, then, even full, we struggle, BUT, its due to the house being huge, heating bills HUGE and constant repairs and updates needing £££££.
I only initially wanted to let rooms occasionally but we are near industry that has workmen and contractors coming all the time, trouble is, there are loads of people in the area who once anyone who comes to our place goes to the shop or pub, they get nicked, normal houses can let 2 rooms and easily subsidise their income and that's what a lot of local people do, often avoiding tax etc as its done on the quiet, we have to pay tax, comply to fire regs which are an expense in themselves, and other stupid things. I used to cook the odd evening meal for groups of workmen but realised that was a chore that did not give the return so I knocked that on the head, then, instead of putting up prices to cover the expense of breakfasts I do room only, especially as we are selling up and there is a snack shop just across from us. The key is having a cheap to maintain house in either a tourist spot, near a unit or hospital or near industry........its not something that will make you rich but if I were alone I would certainly let a room...although sometimes its also scare!!!
AND, you have no freedom!