I've been to Merida & Cancun a few times. Here's a few quick points to watch out for. PLEASE ADD TO THE LIST. **(1)If you stop at a bar for a quick beer (in the hotel zone)NEVER, NEVER, NEVER give the waiter cash until you have been given the bill. Why? Many of the bars are 2 for 1, but if you give the waiter your cash FIRST, he will give you NO change & a padded bill, plus an excuse as to why your drinks were not 2 for 1. **(2)If someone approaches you asking for money for charity, no matter how official they look, ask for their Government ID card. In Mexico all charities MUST carry picture ID cards, usually worn around their neck. WATCH OUT! There are a few guys from Belize claiming to be collecting money for kids with alcohol problems. THEY ARE PHONEY! **(3)Bargain with the taxi driver at the Cancun Airport, and if you are going to the airport. I met an American couple who were charged US$40. to go to the airport. I paid $100peso. If you want a cheapie way to get to the airport: Hop the Riviera bus at the downtown Cancun bus station to Playa Del Carmen ($32peso, 1 hour)Then hop the Playa Del Carmen bus to Cancun Airport ($65 pesp, 1 hour). SAVE CASH! **(4)If you are in a bar with friends, pay attention to who pays the bill. An old Mexican waiter con is to approach one person, when the others are on the dance floor & get him to pay the bill. A few minutes later the waiter asks someone else in the party to pay. etc., etc. I say a waiter collect the same bar tab 4 TIMES!