Susan,
Trademart is open to all AHS Robin members. It started in the 90's I think. It's offered twice a year and is a good place to find trades for your extra plants. Each person pays shipping on what they send. You post a list of up to 50 plants you're looking for and up to 50 that you have available to trade. One can leave reviews on the trade to help build reputations.
Note: I had an e-mail from Diane Pruden today that they're having trouble with the site. If you can't get in that may be why.
