If you can wait till Labor Day and find a Blockbuster(if there's any left by that point) store with both of those games in stock, then they should be running a BOGO sale on $14.99 and under titles.
I'm not 100% sure that the GOW Collection is $15 at BBV, but I know for a fact that God Of War 3 is that price if not cheaper. You'd just have to find a store with both in stock unfortunately.