Hi!:wavey:
and welcome!
One great source for WDW, DLR, and Paris DLR pins are from some wonderful, generous members here on the boards. Speezard (DLR), Merlinemrys (WDW), Timerkat (DSF), and Taram (DLRP) all post on the sale boards and pick up pins from their respective parks. They usually charge cost, tax, and a small fee. They all have great feedback and this is a great way to insure that you get real pins, direct from the parks.
I also buy older or harder to find pins from other members here on the sale boards. Just check their feedback scores.
And I buy on Ebay all the time. I just try to educate myself about the pin before I buy (has it been scrapped? and if yes, how does the scrapper differ from the authorized pin?) Is the pin on the original card? Original packing if applicable? What is the sellers feedback? I also email some of the sellers and ask them where they got the pin. If they are legit, they should have no problem telling you about the where they got it. I do not buy pins on Ebay from sellers from China or Hong Kong.