This is the site I ordered my Green Stuff (Kneadatite) from:

http://web.inetba.com/anyinc/item330642.ctlg

With shipping it went about $20, and it's worth it. A little bit goes a VERY long way. Just be careful when you store it, make sure to use the plastic it comes with, otherwise it can bond to the plastic case and you'll end up wasting a lot. (And when it bonds, it BONDS.)

It's one of several. The company that makes it is Polymeric Systems; search the site a bit and you'll find a link to other distributors:

http://www.polymericsystems.com/GreenStuffMoreTips.htm

Having used this and Sculpey, I recommend Green Stuff. Easier to work with dries much, much harder, doesn't require baking or boiling (it air dries), the smell is pleasant (like corn chips) and it's non-toxic, unlike other epoxies. Catch is it can take up to 48 hours to achieve full hardness (and then it's VERY durable). Sculpey, on the other hand, needs to be baked or boiled to achieve hardness, and isn't as durable; I recommend that for quick work and an inexpensive way to fill small gouges on figures.

My problem is getting places to ship to Puerto Rico. The reason I asked if Hobby Town carried it is because I'll be moving back up to Illinois, and there's a Hobby Town right by where we're planning to move. It's already going to be great just being able to drive five minutes to pick up paints and supplies again. I can't wait...