You can always buy AeroGarden seed kits, but they make Aerogarden-ing much more expensive. A great alternative is the AeroGarden Grow Anything Seed Pot Kit. I used these to start some plants — both herbs and hot peppers, that were not available in a AeroGarden seed kit. You do need an iron to affix the labels.
Price is in Canadian dollars. The link will take you to the Amazon Store of your country.