Did you know that there is a whole list of people looking to do trades, on Artfire!? YEAH! I'm serious! Instead of an Alchemy type thing like Etsy has, Artfire has an area called Forge.
But you can also use Forge for trading! You can request a specific item and if you want to pay you can choose that or you can choose Possible trade, and the person looking to fill your request can either agree to trade or place a bid.
Then I found another cool seller on Etsy, The Garbage Goose. Rochelle has a shop filled to the brim with jewelry, beads, textiles, and and various art objects. I fell in love with some beads and she agreed to trade beads for some jewelry. She picked out 2 necklaces from my shop, and I'm impatiently waiting for these beauties to show up at my doorstep!