Since I didn't see any communities specifically about the trading aspect of Yu-Gi-Oh! trading cards, I figured I may as well introduce one.
This works similar to mtg_marketplace , a sister.com of a community I founded a while back, mtg.
No bidding, no feedback forum here. We'll be going by the honor system right now; I don't anticipate it will be a huge problem, but it's not tolerated if you *do* rip someone off. The point of this community is to find the people you CAN trade with online. It's a great thing when you do.
Simply post have/want lists (behind a LJcut if I have to scroll to see it - if you don't know how to make an LJ cut, click this: http://www.livejournal.com/support/faqbrowse.bml?faqid=75 ) and wait for response. After a successful trade, post so we know who's kosher. Pretty simple stuff.
Don't post addresses. Use instant messaging devices. AIM is great.