You can usually purchase either Guittard A'Peels, Merckens compound chocolates, and Paramount Crystals at several places:
Specialty cake supply stores
The only craft stores in my area on the West Coast are Michaels and Joann's. Neither of these craft store chains carry any Merckens or Guittard products; they only carry the Wilton Candy Melts. Neither Michaels nor Joann's carry Paramount Crystals.
If you have access to a wholesale buying license #, you can purchase product directly from CK or other bakery supply warehouses. Here are examples of online stores that sell the CK brand of Merckens compound chocolates to hobby bakers in smaller quantities. There are many, many, more sources to purchase these products.
If you are "new" to chocolates, it is VERY important to know EXACTLY what you are ordering or you may receive real chocolates that contain cocoa butter which require tempering. Candy melts go by several different names: Confectionery coating, Rainbow Wafers, Confectionery Coating or Summer Coating.
Spend a few minutes and google this phrase, "difference between real chocolate and compound chocolate".