There are many"charm" stations--I don't know the name of the shop but as your are entering WS from FW in Epcot there are "identical" shops on the left and right--the one on the right I believe sells charms. Also, Once Upon a Toy at DTD sells them, and while I can't remember every single store, I know they were at several shops in the parks and at the resorts which sold them.
If you are looking for a "nicer" charm--I believe you can look at the turning jewelry displays at The Disney Store at DTD, Mousegear in Epcot, or the store on the Boardwalk.
the resorts have the silver charms in their shops. the jewelry store on main street MK has a nice selection. in MGM the shop near beauty and the beast show has a nice selection also.