I don't know where to get them any cheaper, I'm sure there some places around. When I was in Orlando last year though I remember seeing on the news, that a lot of people that were buying tickets at big discounts, were getting to the gates and finding out the tickets were not legit.
So be careful where you do get them, it would be bad to buy phoney tickets then have to turn around and buy more tickets at the gate.
Cyrus