I agree with John.
Some thoughts on trades.
Trades work in a tighter knit community. In the Team AF1 thread, I've done many trades from doubles. Not too long ago, I traded one dude a pair of carotene jewels for a pair of '96 black patent lows. We each had extras of pairs that were hard to come by. Trades also work well if you have access to a specific niche of something at a good price. At one point, I've had up to 8 or 9 pairs of OG Black/Red XIs in my possession. I've since sold some and traded others. But, all that has happened with people I trust... all people I've met on the internet (few of my actual boys care at all about sneaks), but people with whom I've developed actual friendships.
In a good trade, both parties think they are winning. And, I might even suggest that if you don't care if the other person is getting screwed in the deal, then you probably don't know that person all that well, and are taking a bigger risk than you think by engaging in the transaction and should maybe rethink doing it at all, as perhaps you are the one about to get taken advantage of. There's not a single person I've done a trade with who would not trade with me again. Having legit sneakerfriends is a pretty valuable resource in this hobby, and burning bridges just isn't worth it if you plan to be around for the long haul.
BTW, there are also plenty of times when instead of buying something and then trying to trade, we'll just contact the person directly and let them know about the link. That happens here too. We've even done things where somebody is selling off a chunk of a collection and we'll just "draft" out the listing among ourselves and say, hey, I'll lay off those if you don't bid on these. Anytime me and one of my sneakerfriends get into a bidding war, we both always feel bad and dumb. He's like, yo, if I knew I was driving up the price against you, I would have just called off the dogs. And, then I'm like, "Yo, if I knew you wanted these, I would have let you have them - I already have a pair anyway."