One way to become a permanent resident is by time. After 4 years of having your temporary resident card you can apply to be a permanent. You have to go to the immigration office in Mexico near you and start the paperwork. Once approved,you dont have to make an every year renewals anymore, the permanent resident card is valid for 10 years after that you have change it and have to take some new pictures (we change our looks with time).
Besides the paperwork you have to pay two fees to immigration. One for checking your case to see if you apply and it is around $67 usd it has to be pay in pesos in a mexican bank. Two: The fee to become a permanent $261 usd, again it has to be pay in pesos in any mexican bank, dont you ever do any payment at the immigration office.

