The FTO that I work for only ask that you pay the bill as you go along - basically settle you account on a weekly basis.
Any reputable school would refund any unused balance should you pay up front and them change your mind - and should be willing to provide a written staement to that effect. If they won't - then go somewhere else.
If you do pay up front - do it on a credit card. However, then bank charges us 2.5% for the privilege and so we have to pass that on.