as u say it varies alot depending on the person.... to give u an idea, my wife and I live in campo, we dont pay rent,
use the pickup the least possible( minimum insurance obligatory 6500 pesos a year, I find gasolina expensive but my car drinks alot, road tax 800 pesos a year)
got a motorbike for local errands 40 000 pesos, insurance 500 pesos a year, gas like 200 pesos a week.
we eat a lot of home grown stuff ( cost is in time), local food all the time, chicken 40 pesos la libra, puerco assado 100 peso la libra...
but if u go to town supermarket for Usa type of food its very expensive( we go once a month or every 2 months for "treats" and spend like 12 000 pesos).
marlborough cigarettes 1100pesos for 10 packs( local brands are much less expensive)
cooking gas, near to nothing like 2000 pesos every 4/6 months or so.
coffee cheap, beer and rum are cheap, so are softdrinks.
so if u got ure own place and like to life simply but comftable u can live on a bit less than 750 dollars a month. 1000 dollars makes life easier.U could get by on less but in my point of view it could be hard.
I ve got no idea of prices in town, but in campo u could rent a nice place, 2bd house,200 dollars but situation and town are all diffrent.
in purto plara I know