Should I Have to Pay for Everything?

no, you shouldn't have to pay. you offered to help, and it's not your fault they wouldn't let you. it almost sounds like they were all close and didn't want to accept another person in their group. I also, think it kind of sounds like they purposely did this so they could get their money back for the kit. You were being more then generous offering to pay for half the kit. If they keep pressing you, I'd give them $30.00 and tell them to **** off. I feel bad for anyone who ever works in their group in the future. Good luck, and don't let them make you feel bad.