K.C.
Costco has them in big bags. So does Trader Joe's.
But please DO read up on them a bit more. Soy is good, as long as it's *fermented soy*. It messes with estrogen levels (not great for developing boys). And, yeah, they eat it in Japan and they're all healthy over there, etc. But they don't eat American portions of it...they'll have maybe 3 edamame as a snack, not an entire bowl full. And they don't drink soy milk by the gallon. Every cuisine has its "junk food" - edamame is kinda like that. I grew up in Japan and NEVER saw people eating edamame the way they eat them here.
Enjoy them in moderation.