Quick summary: I own my house. It's a 3 br, 2ba home, and I only use one bedroom and bathroom for myself. Recently a friend of mine proposed moving in. I've thought about it, and decided to offer them the other 2 rooms and bathroom to them for $500/month + half utilities.
I told another friend of mine (someone not directly involved) about this in passing, and they began to personally attack me for being a sham of a communist, and being a capitalist, and a landlord. They claim that what I'm asking for is steep. I understand essentially the place where their criticism is coming from, rent is a system of accumulation whereby I would be gaining wealth, and my friend would be receiving merely the permit to exist in my house. So on some level I understand and agree with the fact that this arrangement is essentially at odds with my beliefs.
Does this make me a sham? Brutal honesty please.
You are looking at charging your friend $6000 a year plus utilities (which are fairly split).
Total up what you will pay over the course of the year in mortgage, property tax, home insurance, and related fees. Does it add up to less than, say, $5500? If it does, then you are making money on the arrangement (although compared to market rental rate it will still feel like a favor to him). If it's not substantially shorter than 6K, then don't worry about it.
If you're really concerned about it, do what @asaharyev suggested: put the "rent" payment into a separate account, and then anything in that account that goes over the yearly sum you determined above can be returned to your friend when they move out or after a certain term period.