rpodos:Drift diving *IS* easy... the easiest if you ask me. As in, you don't do any work! The trick to Coz, if you ask me, is to go with one of the smaller and more personalized dive ops, and get them to customize to your experience level and desires. Try Aldora Divers.
I second Aldora Divers, and I'm extremely picky. We're going to be diving with them again in September. They will meet you at the airport and arrange for you to drop off your gear where it will be waiting for you on the boat when you dive. So much better than schelping wet gear and no more hassles with washing and storage because they do it for you. They will pick you up at around 7:30 so you can get out to the reef before anyone else. When you get to the site, its a simple backroll off the boat. They provide steel 100s and bottom times are often over an hour. They deliver you to a nice beach for a surface interval where you can buy lunch that is guaranteed not to make you sick. A lot of divers meet their spouses on the beach for lunch. After a 2 hour surface interval, it's back to the 2nd site with another long bottom time. They have several fast boats and you will not placed on a boat where diving is beyond your skill level. Go to www.aldora.com and read reviews of their operation.
$50 a night for the room? Cozumel, Bay Islands, and the north coast of the DR are the most inexpensive places that come to mind.
$50 a night. I agree with the above. You could probably do a package deal from Houston to Cozumel with one of the smaller boutique hotels for about $550 a person including airfare. Some of these hotels have kitchenettes and you can buy groceries at the Chedurai (?) store, which is the local version of Walmart.
You may also want to look at the auctions for weekly timeshares on places like skyauction.com and ebay. I was able to get a room with kitchenette for $249 for the week at Hotel on the Cay in St. Croix on ebay. Not a luxury resort, but perfectly fine for our purposes. It's on a private island called Protestant Cay and there is a free ferry every 15 minutes to Christianstead which is a swimable distance across the harbor. Diving is very reasonable also. We rented a nice car in Christianstead for 3 days ($35.00 per day) from Judi (Cars by Judi? or something). We parked it in the public lot in town for free. It's usually $5.00 per day, but the parking lot attendant had died and has not been replaced. They run on Island Time, obviously.
Check out the Sun Packages at Sky Auction: http://www.skyauction.com/action/search/cat|6
be sure to read the fine print and add up all the extra charges. You can probably find a nice, but not luxurious, timeshare for under $250 for the week. You just need to be a bit creative and match that with a good airfare.
Good luck and have a great trip.