Sorry I didn't cchime in earlier. I've been down with the flu, sicker than I've been in years andwasn't checking the board.
Rwhiting:
Could it be the market at the corner of Ave 30 North and the street that runs east from the main plaza - I think Avenida Juarez (probably butchered the spelling)? I found this market to have better prices on essentials even than Chedraui, although not as big and not as close to the main hotels. I can't remember the name, but it appears on this street map of San Miguel, which I found very useful when walking around town.
That would be Super (as is Supermarket) San Francisco. Corner of 30th and Benito Juarez.
ggunn:
The best booze prices I have found on the island are at this major liquor store on Avenida 15 (I think it's 15; it's the first divided boulevard back from and parallel to the water) a couple of blocks north of the Pemex station. I load up there on Xtabentun to bring back with me.
That would be COVI on the corner of Av. 30 and Calle 2 Nte. It is one block north of the San Francisco grocery store.
Chedraui is the biggest grocery store we have and is the closest thing to a Wal-Mart we have on the island. However, it's still not great when you live here. In fact, the products they carry and the availability of items can be so inconsistent it can drive you crazy. For example, how can a major grocery store run out of milk or eggs? It happens regularly. Then they tease you by getting a new item in, and then it's gone in a day never to be reordered. Most of the time, I still have to go to two or three stores to get everything on the grocery list. But hey, that's part of island living.
The really big treat is to take your car across and go to Cancun to stock up at the Super Wal-Mart or Costco/Sam's. We also have a Sam's in Playa del Carmen now, but it's smaller and doesn't have as much produce and meat as Costco or Sam's in Cancun.
Using dollars at Chedraui will get you the best exchange rate, but the same does not apply at the other grocery stores or other establishments in general. Most places have a set exchange rate at 10.5 or 11.00. The point is, with the exception of Chedraui, it is best to use pesos when possible.
The best exchange rate will be to use the ATM's because your bank will use the real market exchange rate when calculating the withdrawal amount. The machines here do now charge 50 to 75 cent fees, which will show up on your bank statement along with any charges your bank charges for an non affiliated ATM, just as they would in the states.
Hope this answered some questions and was helpful.