I'll try to put some possibilities up to browse as well, but might be changing quantities before the swapping (via the swap tool) starts. Browsing ahead of time lets you put items on your wish list (with whatever number of stars according to how intensely you're wishing), so you can jump right on them when trading begins.
The best way to learn about the swap tool is to watch Dave's video about it. The link is at the top of the main swap tool page (go to the top of any page, click "tools and apps" and then click "seed swaps" from the pull down menu. The tool was created for seed swaps, but it's pretty easy to adapt for a plant swap. In the "number of seeds per packet" field, you can put the size of the plant you're offering (seedling, division in 4" pot, 2 year old plant in gallon pot, etc.).
