Cancun is known worldwide for its gigantic, all-inclusive mega resorts, but there is another face in this tale, the Real Mexico one.
You can spend a week locked inside your resort and never step outside (I have done this in the past), or go out and discover the town. What for? Food, drinks, entertainment, beach, pools, etc. A lot of people prefer the no-brainer all-inclusive option, but there is a whole great world outside for you to explore, and I'm not talking about the tours offered by your resort, which more or less are "sterilized" for your convenience. I'm referring to experiencing the real local food that is very tasty; safe; and especially important, cheap. You may pay for a plate of shrimp at a posh restaurant, but you can get tacos de camaron (shrimp tacos) for a piece, and I guarantee they are fresher and tastier than their pre-processed cousins, and you will have more of them.
Quick Tips:
Visit the local market (Mercado 28; everybody knows its location downtown) for better bargains on your souvenir shopping. Chances are that you will get exactly the same quality (and sometimes the same manufacturer) as you get at the upscale (read expensive) malls, but more down-to-earth prices - and you know where the money will go.
At the market, take some time to eat the delicious local food, the specialty of the area of course being seafood, but if that isn't your fav, don't worry - roasted pork and veal were also foods of the Mayans, along with turkey and the exotic faisan.
Also, if you happen to run out of film, batteries, snacks, etc., you can run into town and go the local supermarkets (Chedraui, Wal-Mart), or even to the Costco. It’s much better than having to buy the extremely expensive, limited options at your resort.
Best Way To Get Around:
Take local buses with the confidence that they are safe, clean, and extremely cheap. Just ask your concierge or bellboy about the number or the routes to get to your desired point. There are not so many routes, but if you don't speak enough Spanish, it would be a little bit harder to get back on your original track. People are very friendly and understand that tourists want to explore and will do their best to help you, even if both of you don't speak each other’s language. Stick preferably to older persons, as they are more patient and have more knowledge.
Taxis are widely available, but I only use them very late at night or during rush hour, when the buses are packed with all the commuting workers from the resorts.