I wouldn't buy any kind of dive gear in Cozumel, because the prices are too high. If you have to, there are two stores near each other a block off the square...I think one is Dive-Rite and the other is across corners from it...they have good stuff and the prices are the lowest you're going to find there...I am assuming you are there and are stuck for a wetsuit...not to be in disagreement with my fellow boarders (who me?) but, personally, being the OCD freak I am, I would never, ever, put on a wetsuit that has been on someone else, especially in mexico...it would take 100 hurricanes to clean it sufficiently (and even then I would want it boiled and disinfected before I used it)...but that's just me...and they charge you for that? Interesting...anyway, have a great trip!