Believe it or not...The best place to get the cheapest mickey wear is at your local Goodwill/Salvation Army. I know that the thought of that is very unpleasant for some people, but my wife and I recently bought a bunch of mickey wear..two t's and one heavy duty long sleeve shirt. One of the t's and one of the long sleeve shirt were brand new or very close to it..still had creases in them. The other t was in excellent shape.
Don't get me wrong, you have to search and there will be plenty of clothes that are in poor shape...but if you look hard enough, you can find some great stuff there.
(P.S.-Total for the three shirts was $4.50)