You can get a better exchange rate by 3-5% if you shop around at money changers (which is every 2nd shop in Bali, or so it seems). Its kind of a legal black market scheme Most are honest, but some will try to short change you (mix in 10K bills with 100K bills) or even pass counterfeit. They are pretty savvy on USD counterfeit and wrinkled bills could get you 10% less. ATM cards are fairly hassle-free at airport but I've run into "out of cash" there, otherwise on street often takes 3 or 4 tries to find a working ATM.