Wal-Mart charges as a credit card. If there were international fees they were relatively small. It's like a $2 trip to/from Wal-Mart via bus. Can't remember if it's bus #2 or #6, but it is a lot cheaper than cab if it's just you two.
We were only there 5 days...we went to the flea market one day and up to the club district for a few hours....we brought $700 and still charged $200 on the card
We bring 1100.00 US for 14 days and take 300.00 in 1s for tipping (drinks) the rest is in small bills (5s 10s 20s 50s) reserved for maid service/restaurant meals/meals-bars off resort/shopping etc. But, everything else is paid for - Boobs Cruise/Lobster Feast on Beach etc.
If you have everything you need and you don't plan to leave the resort then $300 should be good for your 5 days. We spend about $10-15 in food tips plus $10-15 in drink tips per day and then a few more $ for the room service days. So $20-$30 a day. Also we bring mostly all $1 as it is easier for tipping and spends the same as any other $ amount. As for Credit Cards the charges depend on the card you have, we signed up for a Barclay World Travel credit card just for that reason as it doesn't charge foreign transaction fees just in case we need it.
I got hit with a $30 dollar surcharge when using the ATM at the hotel so I always bring more than I generally need. $500 for a 7 night stay is plenty. Jeff
We had cash to play "let it rain" in the bedroom upon return. Took $100 per day for the trip. We tipped and received great service, had money for niknacks for the kids and never thought twice about it. The servers there are grateful for anything you give them- to me it made sense to give a little to get a little.