My friend is going to be moving in w/me and my family for a couple weeks and she's offered to pay rent?

Ask you parents about paying rent. If they say she should then you have no problems. If they say no to her paying rent and you say its a good idea to her then the money would be coming from nowhere. What I mean by that is you said you family is going through some tough money times but if you give the money that your friend is giving you for the rent to your parents they wil ask where it is coming from. What is your excuse going to be? Also what if she brings it up that she is paying rent? Like what if she asks if she is paying the right amount or gives the money to your parents at the end of her stay? You could end up getting in trouble. She is your friend. Why would you manipulate her like that? And anyways what would you get from her? Like $200? That won't help much. Lastly what happens if she finds out you are making her pay rent because YOU want the money for the family and your parents don't want it? That could ruin your whole friendship. Just please dont make her pay rent if your parents don't say she has to.