I've got a housefull of Cosmic Catnip addicts as well. I grow it fresh in the garden, and being a member of the mint family, once it takes it comes back more and more every year! You can often find pots of fresh nip at the grocery store in the prduce section for a few $$ and planted outside early and allowed to go to seed, you'll have a supply for years to come. I harvest the seeds which look like tiny poppy seeds and freeze them to throw in the garden the next year.