Hell, he's made most of his $$ off the poor. He owns tracfone.
He joined the ranks of the world's richest in 1990 when he allegedly used his close ties to the scandal-ridden government of president Carlos Salinas de Gortari to buy a controlling stake in Mexico's telephone company, Telmex, which has a virtual monopoly on fixed lines.
It sounds like he made his money through crooked political dealings. Kinda like the Kennedy's did.
Well durn, I own a tracfone, and I know he isn't getting rich off me. I buy 60 minutes every 3 month and don't use it but as a pager for the wifey to use to contact me (when I have the home phone line tied up). So for 20 bucks (80 a year) I have a pager/phone system, minutes if I need them, and 911 access when I travel. You just can't beat that.