I agree with not buying euros in the states. Our credit union ATM card (it's a Visa and on the Pulse network) is what we've always used. You'll be able to use cards for most of what you need or want -- just do the travel notification like you should for any cards. When you use an ATM, look for one that is owned by a bank. Be familiar with the names of the banks in country. If I know I want to get some euros first thing, I'll review the information on the airport I'm arriving at and see where ATMs are located in the terminal I'll be arriving at and if there are bank ATMs. I also go to the airport maps and see where they're located. Some of the ATMs in the airports are linked to currency exchanges and don't have the best rates. If we wait until we leave the airport, we'll do a google maps search for ATMs close to our hotel. Something else to consider is setting up Apple Pay (or Google Pay) and practice using it before you leave home. Even if your credit/debit card is not chip enabled you can use the secure touch technology in the App. As mentioned above, if given an option to pay in euros or dollars, always chose euros for a much better exchange rate.