Purchasing Polymer Clay

Although my experience with and use of polymer clay is very limited, I have several crafty friends who use this regularly to create jewelry, sculptures, and more, and they are quite adept at the detail and handling of the material.
Recently, one of my friends, abroad, was having trouble finding polymer clay she needed for her projects because supply was very limited. I offered to purchase it here for her, with my discount, and ship it. We discovered that, even with shipping added, she was still getting a better price than she paid there, with the added benefit of a wider range of colors available.
The primary makers of polymer clay are Fimo and Sculpey. Sculpey has several lines including Sculpey Bake Shop, Sculpey II and III. Fimo has something called "Fimo effects" which includes glow in the dark material, glitter, and fluorescent colors. The prices range from .99 per block to $3.00. The Sculpey Bake shop is the least expensive, but not available in as many colors, although I was able to find it at Joann's stores in a wider range than anywhere else. The more expensive colors include the Fimo effects.
In my experience, the Sculpey II and III seems to be the softest, although the Bake Shop was supposedly formulated more for children's use. It does depend on how long the clay has been on the shelf also.