Plus if they buy whatever it is in bulk, they may be getting things for super cheap!
Like a lot of the bead sellers. If I have to buy from China, I might as well get wholesale prices, and buy direct from the merchant, and those merchants count on most people spending $50-$150 with them each round and getting a whole lotta stuff. Not like any sane person buys international stuff at bulk prices and doesn't get a bunch of other goodies.
So, I might pay as little as .50c for a listing, but since I've bought 20 or so lots anywhere from .50c to $5 a pop, the seller does end up making some profit there, and a lot of these bulk selling companies are either overseas or have a hub here in the states as a distribution center, so very low overhead versus traditional brick and mortar.