Manage costs online for a spring break trip

You've taken it upon yourself to plan a Spring Break trip for you and your roommates. You've got an uncle whose condo in Florida will be vacant that week and he's willing to let you use it. You just have to get there and stock the fridge. Your roommates have said they'll put up gas and food money, but getting it out of them has been difficult when you hardly ever see them thanks to your course load and part time job. You need a quick and easy way to collect the money for your big week.