I buy huge packs of batteries too, because I like to always have them on hand! Never know when your toy is gonna buzz out on you, and as much as I love Eden I couldn't wait for batteries to ship if mine died and I hadn't remember to order them!
I started buying toys that required batteries again so I went and bought more rechargeable ones that fit my charger at Walmart. I don't buy batteries anywhere anymore unless they are rechargeable ones. I think it's a better investment in the long run and almost like having rechargeable toys.