Mayweather vs. Pacquiao -- IT PAYS TO BE MEXICAN ... Whole Country Gets Fight for Free!

If you don't wanna pay $100 for the Mayweather vs. Pacquiao fight, ya might wanna head south of the border ... because the entire country of Mexico is getting the fight for FREE!!!

The World Boxing Council tells TMZ Sports ... two major Mexican TV networks have agreed to air the fight, Televisa and Azteca --so if you have a TV, you're good to go.

The WBC tells us, "Televisa and Azteca must be recognized for their great commitment, for bringing to Mexico this bout for free. This has never, ever happened in any country of the world."

FYI -- Mexico also happens to be a major sponsor of the fight ... and the official beer of the bout is Tecate. Bottom line, Mexico is HEAVILY invested in the matchup despite the fact neither fighter is Mexican.