I would agree with this thread! The used section does seem to be moving slower these days, kinda surprised me, I usually can unload gear here. What I have noticed is that say you have item "ABC" that seems to sell on ebay/here for 400+shipping. You might have the same item, plus a bonus item and they will offer you say 325.00 (lower than the standard market rate), then want to also pay 100% of the shipping/tracking/signature/paypal/package fees.
2nd thing I have noticed. You will get people asking offering you X for product "ABC", you will agree via PM, then you will never receive paypal,PM,email. You PM them back and never hear anything back. At least if you change your mind, treat others as you want to be treated and inform them something came up and you backed up, so they don't' end up holding it waiting for payment and miss other sells.
I think maybe if we charged a small amount less than FM on the buy/sell. Say like 5 dollars it might help too and add a real feedback system like several other sites i'm a member of.