Another great thing about Buenos Aires is that you can take a comfy boat (fully equipped with a cafe and duty free shopping) over to Uruguay. We took the Buquebus to the lovely Colonia del Sacramento for a relaxing day of sightseeing, delicious food/wine/coffee and a historic tour. As a bonus, you can get American dollars from the ATM machines to exchange back in Buenos Aires.
We got pretty good at estimating how much money we would need every day so that we had the right amount of cash and didn’t have to use the credit cards. An important thing to note if you are planning on visiting Argentina is that there is the official exchange rate and the unofficial one. A lot of places in Argentina will exchange American dollars at the unofficial rate so bring cash (in $100 bills!). The difference is actually huge and pre-booking/paying for things with your credit card at home will cost a lot more than if you just show up, exchange money and pay in cash. We met a lot of people just checking out hotels with no reservations – totes normal thing to do.
Colonia del Sacramento, Uruguay