Been to Mexico, but not Mexico City. Hagglers everywhere, don't pay full price for anything. Don't piss off the drug dealers... They're rather brutal in Mexico.
Generally it is considered a polite greeting as a foreigner if you tell everyone "Tu Madre es una puta" when you greet them.
That sounds as though it could possibly mean 'Your mother is a whore'?

Do I use the hip and knee replacement card?