Medical care in Mexico.

I have a friend in Zihua with a limited income and a child that needs to be seen by a doctor in Michoacan on a regular basis. The doctor visit costs 5500 Pesos. I was under the impression that only in the US people have to pay for doctor visits. Is the system in Mexico equally backward? Living in Europe many years ago, when I got sick, my mother would call the doctor who would come, check me out, write a prescription and there was never a bill. Doesn't Mexico have a similar system, at least for the financially stressed?