Unlike United States, Mexico has a different way to manage money in politics. First of all, sponsoring political parties is illegal. On the other hand, we have a centralized institution (INE) that manages and controls the funding going to each political party. All the funding goes directly from the taxes Mexicans pay, and it is divided depending on how many votes the political party had on the last presidential elections.
If a political party has less than 3% of the total votes, the National Electoral Institute (INE) takes away its funding and cancels the registration of the political party.
Fun fact: This year's presidential elections were considered the most legitimate in history.