Are you looking for singles or are you looking to buy packs in bulk (i.e. a booster box)? Ebay is the best choice for singles, but be sure to read the seller feedback. Don't buy from a seller that has any less than five stars. As far as packs go, I'd suggest Amazon, Again, make sure that any third party sellers are trustworthy. I've bought 36-pack boxes for at little as $95 (not counting shipping) from Amazon sellers. Some sellers may also offer free shipping, so that's a big plus.