Of all the ridiculous things that street vendors say in order to get your attention, this one peeves me off the most. "Hey amigo, you like this necklace? 100 pesos, 10 dollars — almost free!" It's tacky; it's insulting (to people's intelligence); and it's completely untrue. But I guess it does the job of luring in those American prey, and their almost smellable dollars.
I don't think I heard it so much to the west, in the other places I've been so far. But here on the beach resort coast, it's everywhere. I hope it hasn't caught on in Chiapas.