One of the best examples is the block erupters.  They at this point  should be very very cheap.  They were mass made and a lot of us owened more then we ever would want at this point (I sold mine off long ago when the blade was new).   

But people still buy block erupters for collecting (which some do all colors) and learning.  They bring far more then what is logical.  I have sold MANY generations on ebay and it's worked out well.  Only one I have gotten returned was a R1 router as they said it was not a reliable router.... which who buys a R1 to act as a router for other devices to connect to.... but that is another story.