Depends on the brand but no matter what you do DO NOT buy anything designer off of ebay. Ebay was sued by LV and Dior because somewhere around 98% of all their designer stuff was fake. Unless you want to take that risk then don't buy off ebay. I don't think you really can get good authentic handbags that are cheap unless they're like ones that were messed up in the factory, I know for a fact that LV doesn't have any of those because they destroy them even if there's the slightest defect. The best website to get Designer bags and know for SURE that they're real is
www.eluxury.com but it's not really cheaper it's the same as in the store.