[…] turns out that when you use your credit or debit card outside of the US, Visa and Mastercard charge three percent in transaction fees on the spend. It doesn’t matter if you use an ATM, buy over the Internet/phone, or walk into a store — the credit-card companies always dip their beaks. When you pay your hotel bill, when you buy a plane ticket, every time you use Amazon.uk to order a British release (Citibank told me that they even charge the fee when I withdraw from my Citibank US account while at a Citibank UK ATM, using Citibank’s own network!)
Definitely something to be aware of – when I lived in Seoul, ATM fees could be as much as $5. While you don’t want to be carrying around wads of cash, it’s a good idea to not make a lot of frivolous, small withdrawals.
Also, if you’re planning a trip around the world, Rolf Potts at Vagablogging has some good tips for doing it on the cheap:
Personally, I might recommend starting with a crash course in Southeast Asia. Thailand is always a good place to start, and SE Asia has a lot of diversity, is quite accessible and travel-friendly, and will give you a sense for how cheaply you can get around (better in my opinion to start in a cheap place and be shocked by Europe prices than to blow all your money in Europe and not have enough for cheaper places).