Jay,
Beers are cheap, booze is cheap, there are lots of bars/clubs where you pay a cover fee and that also includes all your drinks (local booze, you have to pay for the high end stuff)
If you plan to leave your all-inclusive and head out and about, one excellent suggestion is to find something to 'cover' your wristband. If you have a watch or wristbands those are great to cover it. When you're at local markets, and in cabs etc, and they see your wristband, they know you are a tourist, and you'll definitely get charged tourist prices. Of course, when you're walking around white as can be, or burnt red like a lobster, and looking at absolutely everything around you, that's also quite informative to locals about your 'status'
Wearing a wristband you'll also be subjected to lots of timeshare peeps, but if you've got an hour and a half to spare you can usually get yourself a free snorkeling/diving tour out of those, but you have to be willing to sit in on one of their talks, which, when you're only in town for 4 days, you might not want to waste the time on it (though they'll also buy you breakfast if you do a morning talk LOL)
Most cabs are fairly inexpensive, depends on where you're staying and how far you're going. They're not metered. For example, for me to take a 10 minute ride in a cab from my home to the local mall/grocery store typically costs me 30 pesos... which is like $2.50 or so (give or take the exchange rate). Someone said ask before you get in, that's a good idea, and don't forget you can always try to negotiate the price, but I've found when you compare cab fares here to cab fares up north, even if they're charging you more than normal rate here, you're still getting a killer deal
Just remember, most things are negotiable.
Xel-Ha is definitely great for snorkelling. You'll find TONS of good spots for snorkelling along the coast, or swimming with dolphins, or fishing, or diving.. lots of water sports available all year round. Bring a waterproof camera, it's totally worth it!
I hope you have a great trip! It really is beautiful here, oh, and another bonus is that it's perfectly legal for chicks to sunbathe topless on the beaches here!
