Speaking of buy cheap designer glasses frames, online shop is a good places to go. To get it at cheap prices, you can search at Amazon or ebay, or some onine optical shop. Of course, if you just look for stylish, good quality yet cheap eyeglasses frames, there are lots of places you can go such as Firmoo.com, framesdirect.com and lenscrafters.com etc.
you may find them on ebay or Amazon . I am sure there will be stores selling cheap but real designer frames . I have heard framedirect sells them. But I am not sure if they are real . You can have a look .