My local gun shop of choice often takes guns in on trade, or buy them. Quite often, these guns have holsters or cases with them. They clean the guns up for the display case, and the holsters go into a couple of bins for deep discount off new prices. There is, of course, junk in the bin. There are also serious buys available, such as the "like new" Galco SAO holster I bought for $30 last week.