Post Cereals first created Pop-Tarts in the early 1960s by adapting its process for enclosing food in foil to keep it fresh without spoiling, originally used for dog food, to its new toaster-prepared breakfast food called Country Squares. Because Post revealed Country Squares before it was ready, Kellogg was able to develop its own version called Pop-Tarts within six months by taking inspiration from Pop Art. Originally only available in four flavors and not frosted, frosted Pop-Tarts were released in 1967 and there are now many flavors available. An average box of 12 Pop-Tarts costs around $5.