What to charge for a fundraiser dinner?

Ok so my family and I are trying to raise money for my medical bills for my just starting fight against bladder cancer. Our church has agreed to let us host Fundraiser dinners. We are wanting to start off with a spagetti dinner but we have never done any of this before . We have found information online that is of great help but we still have no idea what to charge per head. We are looking at maybe $350 investment in the event . Plus a 10 % donation to the church for use of the property. Any one who has experience with this sort of thing please help. We are expecting to have some sort of fundraiser often to keep up with the bills and to be able to help others with bladder cancer who are facing the same financial challenges. I need all the help I can get so please feel free to give me some examples and maybe how to do it. We have lots in mind such as a fish fry and a bikini car wash and some other things but it seems like all our best ideas have to wait for warmer weather. What about a community yard sale do you charge for spots on our property like a flea market or depend on sellers to donate or would we do better letting them sell for no fee and sell food at the event for our fundraising.