I've got some bits laying around in my den that I'm considering putting up as PIFs. I've also been wanting to get into "trades" for a while now. How do you guys ship? I mean, how do you ship something without it being cost-prohibitive? Seems like a silly question perhaps, but I honestly don't know. Every time I've gone to the local post office to ship something in the past (a rare occurrence to date) it has always seemed to be sooo expensive.
I don't know any way around the cost. It is high like you say but when I decide to PIF something the joy I know I will bring to the receiving person out weighs the shipping costs in my mind.
Really depends on what you're shipping. Anything under 13 ozs can ship 1st Class for a few dollars. Books can go Media Mail, which is quite reasonable.
If it's something that could get damaged or is somewhat valuable, I generally ship in a USPS small flat rate box.