Thanks for all the replies. I've been doing some research and I'm leaning towards doing a four hour charter in the lagoon area that's behind the barrier island of Cancun. From what I've read there are better places to go nearby when the permit and bonefish are in season, but that's unfortunately not when I'll be there. So the Cancun fishing grounds seem to be the best and most cost effective place to go for snook and little tarpon, plus it only takes 10 - 15 minutes to get to where you fish, so I can save some money by taking a four hour trip instead of six. I'm only there for four days so I'll need time to check out some ruins and lay by the pool/beach and drink fruity cocktails out of hollowed out pineapples. Looking around online for companies that run these kind of trips I found these guys, father and son locals, sounds like a good operation.
http://www.unomassportfishing.com/index.html