Well assuming you can get the pencil sharpener and cloths pin for a buck. If you don’t mind buying in bulk, you can get alot more and a cheaper price.
Anyways pretty simple build. And would be more accurate at stripping than my knife.
http://lifehacker.com/make-a-simple-wire-stripper-out-of-a-clothespin-and-a-p-1766465868