Seed Savers Exchange
I saw a post a couple of weeks ago about saving seeds - how to best prepare and save for storage. Read an article today that had a link to Seed Savers Exchange, a nonprofit group dedicated to keeping and exchanging heirloom seeds. There are thousands of varieties of vegetables, beans, flowers etc that you can shop, and they only charge for postage (about $5 a seed packet).
I save my own seeds and trade locally but for someone looking for a low-cost way to start some heirloom plants, this is a great resource.