Electric is as expensive as the states and if you run the air a lot maybe a little more. I live with people and we run 2 nice wall units in the rooms. The electric bill was 175 US dollars. The Water bill is higher than anywhere I have been in the states. About 95 US last month. THe water is distilled from sea water and it is quite good.
Food is quite expensive. We shop on Fridays at 3 different grocery stores and can get almost all that we need. BUt if you just shop at the on near the school, Cultimara, it is the most expensive but have a decent variety.
Kellogs cereal is about 4 to 5 USD a box and Milk is about 8 USD a gallon (Macarthur's). 2 liter coke is anywhere between 1.70 USD to 4 USD, depends on where you shop. Remember there is not the choice of brands like there are in the US. If you want COlgate toothpast then you can get it. But don't expect Aquafresh, Crest (with all the varieties), etc.
HOpe that gives you an idea.