In Hollywood Studios - the store that you walk through when you exit Star Tours. You don't have to ride Star Tours to go in, just trying to give a point of reference. You can also build your own droids.
You can also find them in Tomorrowland in MK... no clue about the store name, I never pay attention to those! But it's a fairly big one, tons of Star Wars stuff, so if you're looking - you'll find them.
In both instances, this was prior to the latest Star Wars additions to the parks, so I wouldn't be surprised if you find them additional places, but those two locations have had them for a couple years now.