Thought that I would just include some useful information here that did not fit into any of the other categories:
We used USA Travel for RT transport from the Cancun Airport to the Ferry Dock for Isla (about a 25 minute ride). Very easy to arrange online. Upon exiting the Airport, we looked for a person with a USA Travel logo on his shirt,gave him our name , he called a private van from the parking area and we were on our way to the Ferry. The RT charge was $75.00 for 4 of us. For an extra $30.00 the Driver will stop at a local Wal-Mart and you could pick up some staples. We did not do this and found everything we needed on Isla. Everything was open on Christmas Eve. Due to the XMAS Day Security Threat we decided that we wanted to leave for the airport 1/2 hour earlier than recommended by USA Travel. One quick phone call to them and the driver was waiting for us at the Ferry in Cancun at 7:30 a.m.
We purchased our RT Ferry Tickets upon arrival at the Dock. $40.00 for 4 RT tickets. The ferry runs every half hour from 5:30 a.m. until midnight. Takes about 15 - 20 minutes to get from Cancun to Isla.
Sunscreen is about the only thing that is expensive on the Island. Bring plenty with you.
I could not find ground coffee any where and had to buy Instant :(. Lesfaye found some at a little grocery and shared it with me. Bring your own.
There were many laundry services and coin operated laundrimats on Isla.Depending on the size of the load, it was $4 - $6 to have clothes done for you,usually with same day service.
There are many Cafes with Wifi .The Internet place next to the Supermarket was generally opened from 9:00 a.m. til 11:00 p.m. It was less than $2.00 for an hour. International Telephone Service was available for about $.28/minute. Sometimes this place opened as early as 8:00 a.m.
We were surprised to not find beach front restaurants and bars. Perhaps we did not look in the right places? Of course there were plenty of restaurants/bars on the Beach, but none that we found to be open after dark.
Mmmm, maybe I need to turn this into a Trip Report?