Something else you should consider is Insurance. What does your aircraft policy cover? Do passengers have to, for example become a club member to be covered? Many personal policies that passengers might have may not include flights in private aeroplanes. You as the pilot are in the firing line if anything goes wrong. If you want to take people flying, then do so but don't expect them to pay anything. If you go on a flight with a group of people from a flying club then they will reasonably expect to contribute. You might get a few free lunches and occasionally someone might make a contribution. The point being this is not the way to pay for your flying!