I always go to goodwill store every month and I could tell you its pretty rare to find collectible items. I got lucky when some goodwill stores are selling on amazon and got a couple CE's so you could look into that. Also it will be defenitely frustrating finding things like Assassins Creed 2 Black Edition on ebay on a good price for example. Try ebay.co.uk, its another world out there lol THANKS UK
And finally be active on this forum so you don't miss out on new collectors items.