In my experience living in Latin America, you have to know decent numbers in Spanish in order to not get people ripping you off. Really important here, consider

In my experience living in Latin America, you have to know decent numbers in Spanish in order to not get people ripping you off. Really important here, considering that prices are often above 1000 pesos/etc for things, if you can't understand (with conversion!) mental math in those units or how to say numbers that high you're probably going to get screwed over at least once by someone looking to capitalize on your ignorance. It's the first bit of advice I have for anyone coming in from out of the country other than the other two bits: don't take offence to someone making fun of you (If they don't make fun of you or mess with you a bit after getting to know you, even just a little bit, it means they don't like you, which is really quite something a lot of other cultures don't get so easily), and don't do cocaine unless you want to be looked at as a potential victim. Same thing with the taxi, except it helps to know the local slang for a 'meter' -- 'la maria', and a phrase around the lines of 'no me jodas, no soy gringo, muchas gracias' (Don't fuck with me, I'm not a gringo, many thanks) will get you a lot further too.