Thanks for your interest! As far as durability goes shark is the most wear resistant, alligator and crocodile being a very close second, then ray. I put ray last as its white on the inside of the pearls and if you gouge it good enough you will expose that layer in the calcic node. The better quality ray skins dont do this as easily and tend to be dyed deeper.
The nice thing about having my own forum is I can post pricing.
Shark is 10.00 an inch
Gator, Croc, and caimen, are anywhere from 15 to 20.00 an inch depending on the market.
Ray skin varies as well, but usually runs about 10.00 an inch.
I try to get the best quality skins I can get my hands on, and am always on the lookout for unique stuff.