Switch to powdered milk?

While at Kenn and Amy's Jon and I got to experience powdered milk. It wasn't bad and was actually quite delicious after eating gooey chocolate chip filled cupcakes. I made Jon drink some without telling him it was different and he said it was fine.
So now I am on the hunt for powdered milk. Any tips from you food storage experts on where to get the best price, preferably in bulk since we'd be using quite a bit of it. Also, if you're an expert on Walton Feed I noticed that they have TONS of different kinds listed, but I don't know the difference between them. Any help you can give would be GREAT!