I'm having my 22yo nephew come to stay for 6 weeks over the summer while he's out of Uni. He's offered to pay rent while he's with us. I know he's earning reasonably from his computer business, so I know he's genuine in his offer, but I have no idea how much to charge him? He'll have the converted loft which has a bedroom bathroom and separate sitting area so it's not just a room, but at the same time he's family and I don't want to charge too much! How much do you think would be reasonable? Many thanks in advance!