Like the PP said, you most likely will trade with CM's. I have only traded with another guest one time. At DD, they have tables where the serious people go. My experience hasn't been positive with those folks though. They never want what you have, but if you want something they have, they will take you into the store and show you a pin you can buy to trade for the one you want from them. I'm not saying everyone one does this, but it's what I've observed. As for ebay, you can get cheap pins but most likely you'll be getting scappers - pins that didn't make Disney's standard, overruns, etc. Most people frown on buying these to be used for trading; unless you have a trained eye, it's very likely that could be trading the CM for a scrapper. I've been trading for a few years but I can't tell a scrapper from a real one unless they are side by side or a really bad pin. If you get into trading, I would stear clear on anyone wanting you to buy them a pin to "trade" for one they have - I seriously doubt you're getting the better deal. So, get a starter set and have some fun. Also, some CM's have green landyard with pins - those are for kids under 12. You can go to Disneypins.com and it will show you upcoming and past pins.