Ok, how do you get the best deals with "the natives". i know in grand cayman it does not really matter as the cayman dollar is worth more than the USD and it is a pricey place. But what about in cozumel. When we were in St. Maarten I just put my jewlrey purchase on my mastercard but I read somewhere that in Mexico the love USD. So would I be better of bring cash? Are travelers checks revered as much as cash to them?