I don't know what the deposit is, but I don't think that the deposit is refundable if you get in off of a waitlist. When you think about it, someone else's wait list has absolutely nothing to do with them.
unless something really crazy happens (like major catastrophe in your family that will force you to not enroll...but even that may not qualify you) you will NEVER get a deposit back. from anywhere. The deposit ensures that you will attend that school and not change your mind. So if you do change your mind, they take your money and it sucks to be you.