Lake Atitlan is an amazing place in Guatamala. Although the cost of living is near the top of the list as to why it is so attractive to ex-pats, the life you can have while there is what makes it so popular.
Rent of less than $250 a month. Hiring a maid for $10 day. Cost of most groceries around $70 a month. Not to mention the low cost of eating out in restaurants.
In this video Andy Lee Graham of HoboTraveler Shows an apartment an Ex-pat from the US lives in for under $250: