if you want to purchase really cheap versions of these games, I would advise your best bet is (if you're going for the cheapest option) try searching around on ebay, but keep an eye out on instead of paying postage, instead you go to collect the item. I've found a many brilliant sales by using that option, and majority of it is all in pristene condition already.

for example; GH2, RB2, Guitar and Drums for about $40 all in perfect condition.