Mr. Case
You would do better if they had a system where they ran an account for you that was topped up every couple of weeks. With electronic banking the transfers are almost instantaneous. This should keep everyone happy.
DO NOT PAY UP FRONT!
This takes all control out of your hands and allows them to do as they please. Remember who's doing who the favour here. You're a customer first and a student second.
Don't let them forget that.