Aside from the climate, turquoise water, and beautiful beaches, this may be one of Cancun's greatest assets. You can go anywhere within the main hotel zone for about 60 cents (U.S. conversion). And you'll rarely have to wait for a bus. It seems as if they go by every five minutes.
Which bus?
The busses have different names and numbers written on the windshield. If you are traveling between hotels, malls, and restaurants in the Cancun tourist area, it doesn't matter which bus you get on. If you are going to the tourist areas in downtown, your best bet is a bus marked "Ave Tulum" on the windshield. If you need supplies at WalMart, there is a bus that has "WalMart" written on the windshield.
Which direction you go on these busses depends upon which side of the street you're on. When boarding a bus, check your Can-Do Cancun map (you did order one didn't you?), to see which direction your destination is, then you'll be able to decide which side you need to wait at.
Basic bus instructions
1. Save your peso coins. It's difficult for the driver to make change for large bills.
2. Get on and grab hold! The drivers don't wait long at each stop, and will probably take off while you are still paying.
3. Tell the driver the name of your destination. Say it simply, and in a polite tone of voice, and he'll probably stop.
4. Try to identify some landmarks so you know when you are close to your stop.
5. Don't be afraid to ask your fellow riders. The people of Cancun are very gracious hosts. Mention the name of your stop, and they'll help you.
Two obstacles: Workers, and Spring Breakers
There are a few times when the busses aren't the greatest way to get around.
When the hotel workers get off, the busses are overflowing with tired people. They are kind, and courteous, but the busses get so full, that they often can't pick up any additonal passengers. You could be left stranded along the curb, until things get back to normal.
The other situation is late at night when the Spring Breakers are in town (locals call them the "Spring Monsters"). The drunken kids yell profanities, fall-down, throw-up, and anything else you can think of that can be done on a bus.