The problem is, if they make it free or cheap, they will be overrun with skaters and it will be difficult to evaluate. Imagine how many crazies would be out at every other tryout if they were $10 each. Now you're looking at extra sessions, which means extra ice time, and the trouble goes on from there. So they charge what the market will bear. If you don't like it, stop paying for three tryouts and just stay where you are.
The fee for tryouts goes to a good cause, it's called the owners kids college fund