We lived on the North Coast and my wife (girlfriend at the time) worked for while, before we had our son, 6 days a week for 4,500 pesos a month, no tips involved. It was a pretty sucky job and I finally told her to just quit, it wasn't worth it. We should have her visa in a few month and they will be here in the states with me. What blows my mind is every three months when I go back and we go shopping, we walk out after spending 3,000-4,000 pesos and really don't have much. A quick run to the super and it's 2000 pesos and we have 3-4 bags. It just goes to show you how hard it can be. Thank god for the fruit and veggie trucks coming through the barrio.
Of course I go to her moms just up the mountain and most everything we eat while there is grown on site, or very near. Mangos, avacados, yucca, oranges, bread fruit, bananas and free range chicken right outside the door. And that's how so many of them do it.