Originally Posted by Section 107

Depends upon the size of the bottles. The official allowance limits are here: Mercancía que puedes ingresar a México (sat.gob.mx)

I am not sure how if Mexico's other airports work this way, but the last time I arrived at MEX in Terminal 1 (the older terminal) one could purchase at the Duty Free store on the way INTO the country (in fact, you are almost literally routed through the store on the way to baggage claim and customs inspection. Means not having to bother with bottles in checked luggage or carryon. Note that this was not possible at T2 (the newer terminal).

However, I have found that most prices for alcohol in Mexico duty free were actually higher than in the local stores, particularly Walmart, Costco and Mega grocery store. YMMV.