Here's a link to the trade forum's (you need to be signed in to create a pits obviously).
Towards the top/left of your screen if you're signed in - you'll see a blue bar that says "New Topic"
Click this to create a new thread. Be sure to label in the name of the thread if items are For Sale (FS) or For Trade (FT) or both (FS/FT).
If you don't want to put a price on the things you are trying to sell, then they are "For Offer". (FO)
Welcome to NA and good luck on your trades!
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Santa's 8-bit Xmas Hall of Heroes
bunnyboy, psychobear85, superbobby, captmorgandrinker, guillavoie, KHAN Games (backup from Jon Solo), fsped09 & zi