There are a lot of Disny pins on sale on ebay, both seperately and as large lots.  For many people who are into pin trading, these large lots of pins look like a good deal, and they can be, if they DO NOT have Sedesma stamped on the back.

Crew members at the Disney resorts are not supposed to trade the pins that have Sedesma on the back.  What this means is that if you are purchasing these lots to have spare pins to trade, you will only be able to trade with other people in the park, not crew members and usually not the pin traders. 

When looking to buy a lot of Disney pins for trading, read the description carefully.  If it does not specifically say that they are not Sedesma pins, ask!