I've never had any trouble with cash, even US $100. BC's always takes them, so do many other well frequented bars and restaurants. My visa did charge me some small service/currency exchange fees a couple weeks ago in SP. More importantly tho, be SURE to call your credit card company and tell them you are traveling... I didn't and went to check out the final day only to find my card had a Do Not Honor - possible fraud alert on it! Yikes, couldn't pay my hotel, nor could I stay... kinda makes for an interesting time.

M. Sjulstad
M&M Trivia - JAMPT UP Band