I really got into saving and growing heirloom seeds three years ago, and have been reading and practicing ever since. As my confidence grows, and I have a chance to grow out varieties to test isolation techniques, I plan to offer seeds for trade or sale within the US.
Above is a shot of my current collection, both saved and purchased. Below is a list of vegetable, herb, Tree, and flower seed I currently have in excess. Email me a email@example.com if you are interested. I charge $3 for the first packet and $2 for each additional. This includes shipping, quantities vary depending on variety.
Asparagus (unk local variety)
Cherry Tomato, Gardener's Delight (aka Sugar Lump)
Ground Cherry, Aunt Molly's
Hollyhock, Antique White
That's it for now, but I hope to add more varieties next season. We'll see, I'm struggling with how I am going to maintain genetic isolation as I convert the gardens into a polyculture forest garden. Oh well, I guess there is no "best" way; just the best we can do.