I think it depends a lot on your lifestyle. Our family of 3 lived there for 12 months last year and we averaged about $2500 US a month. Rent and utilities ran about $1000 US-well worth it as the place we lived was really nice. While we ate our fair share of beans and rice ( and alternately, rice and beans), we did fall into the trap of buying more American food which definitely added to the overall expense.
Admittedly, we drank a lot of beer. I'm sure Palapa Bar, Coco Loco and Island Perk were impacted financially by our departure. No regrets though, we had an awesome year that we will remember forever. We had the best midlife crisis of anyone we know.