Not really with specific groups or people for the most part. I found that with a lot of people, I'd offer up what I found at around cost, but when these people had stuff for sale that I wanted, I would be offered it at the going price or above that, even when I know they found it cheap.

I pretty much only offer stuff up for great prices now to specific friends or specific people I know. I don't find a lot of stuff worth trading these days though, not as much compared to what I used to find.