RE: COC Grippers..which one?
I wouldn't recommend buying either. There are better and cheaper methods of building your crushing grip. I love IronMind's products, but I think the CoC are one of the biggest gimmicks in the strength training world. Unbelieveable marketing!
I know you are on a tight budget, but even if you weren't, I think a better investment would be to buy the book "Mastery of Hand Strength" by John Brookfield. Brookfield as much as says that are better and cheaper options for building a strong crushing grip than the CoCs like plier lifting and wire cutting. I agree completely.
His book covers all aspects of building grip, hand, and forearm strength and how to build grip training devices very cheaply or for nothing just using items from around the house.