I just posted an ad for an awesome ASM book but how do you go about trading or buying a book outside of the store? Is there an option to do that?
Just click on the profile of the person you want to trade with, and then click on the 'Gift/Trade' button. It's a really nice interface, so it will be intuitively obvious. There is a time limit of 45 seconds because of system requirements though.
For straight trades, you just click on what you want to trade for what, and they get a trade request which shows up in their game bar in the lower left corner of the screen.
For sales, you make a gift of the book and they make a gift of the money you've agreed to (like PayPal Personal). This is why all sales should be documented in the sales forum (eBay sub-forum)...this in turn becomes an enforceable contract.
Hope this helps. I'll eventually add a 'How To,' but I haven't gotten around to it yet.