I love getting pins off of Ebay auctions where the pins are very low cost (and usually HM or rack) because it's fun to bid and be all tense up until the last seconds to make sure no one swipes it from you... I try to spend the least amount as possible, and even allow pins I LOVE to pass on because they hit that certain threshold. I've never traded in the park, and I would love to, but first I need to have my lanyard ready full of pins!!! And I am going to need them all coordinating somehow HAHA even though they are just going to be traded away! So for these traders, my limit is like $3. I love getting rack pins for less then rack price (that limit is like $5!)
But when it comes to finding pins for my collection, to hang on the wall, I prefer to buy from fellow forum members because I know they have been kept safe, and I know they are real. The most I've ever spent on a single pin was $25, and that was the price it cost to buy from Disney. I try to keep myself away from wanting the hyped up pins, the shiny new ones, unless I can buy them from Disney myself. If I miss it, I miss it. I'll just have to wait a year or two for them to be back to their original prices! LOL! The only exception to my rule of paying at-cost or slightly above cost is for a very rare and beautiful pin. Then the skies the limit!!!