Cost of living in Mar del Plata (Argentina) is 19% cheaper than in Zapopan (Mexico)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 519 prices entered by 32 different people.
For example, to keep the same standard of living that would require Mex$ 50,000 in Zapopan you would need to make just about Mex$ 40,333 (ARS $40,426) in Mar del Plata.