We had people who did that for our last swap, too. It was wonderfully generous! So it's definitely not a problem! You can join our swap and you won't have to pay the fee since you won't have anything mailed back to you (you'll just be responsible for paying the shipping to have it sent to the host, of course, once you send it in).
If you end up changing your mind later and want to get seeds in return, that's okay, too; just send in the fee when you send in your seeds. It's designed to be flexible that way.
