I like Nachi Cocom better. It's a bit quieter than Chankanab and has a swimming pool if you get tired of the sand and salt. There's no entrance fee there - you just pay for your food and drinks. Salvador runs the place. He's a really nice guy.
Yes, there is a resturant and a gift shop, etc. plus many many other amenites and stuff to do (like sea lion show, dolphin exhibit, etc.) search the boards for Chanakaab and you'll find out a ton of information about it.
Here's a little more information from another post I did . . . Yes, I booked the dolphin excursion outside of the boat at www.dolphindiscovery.com and it's a better price. They even have package deals which are not on the internet. If you just want to get to a beach I highly recommend the Chanakaab Park - it's wonderful. Has a lagoon which is perfect for kids or just relaxing without waves, etc. If you swim out about 20 yards they have a platform so you can swim out and then lay on the floating platform. They have beach chairs and also you can rent snorkle gear there also and it's only about $5.00, way less than on the boat. Or do like we do and bring our own cause you can pick up a decent set at Walgreens or CVS. It's a fablous park, easy to snorkle off the beach. All other snorkle cruise/excursions off the ship take you out on a boat and then you jump in - easy to swallow salt water, etc. if you're not really experienced. There is a small shopping area, a resturant, a sea lion show you can pay to go to - like $5.00/per person. Has locker rooms and shower facilities. This is my favorite beach in Cozumel, if you couldn't tell. :-)