Prague, Vienna, and Budapest

You've gotten good information from @JackHorzempa and @barrybeerdog, but I'll throw in a couple of additional thoughts.

Probably the most important thing that Barry pointed out, is how popular Prague has become with international tourists. You can still find some deals in Prague (beer prices remain relatively cheap by US standards), but don't expect inordinately low restaurant or store prices. Most places expect to be tipped, especially if they perceive you to be an American tourist. This is especially the case if you're paying with a CC. At least when we were there last summer, the going rate still seemed to be around 10%.

While some places will take dollars or euros, you probably won't be happy with the exchange rate. So as much as possible, try to use a credit card or local currency. Once upon a time, the best place to obtain local currency was from an ATM. That may still be the case for you, but you need to be careful. My bank now charges an international foreign currency transaction fee for international withdrawals, which tends to negate any benefit you might derive from the banking industry exchange rate. My Bank is Chase, which makes me think this is probably an increasingly common practice. Also, there are a number of unscrupulous ATM owners in Prague, charging exorbitant ATM fees for foreign transactions (euronet comes to mind, but there were others. You can look them up online.). Anyway, I've completely stopped using ATMs in Prague (and Europe generally), and instead use currency exchange outlets. Be sure to check online to find a reputable one near your hotel (just like the ATMs, there are many unscrupulous currency exchange stores).

Prague is a beautiful place, but is increasingly beset with the same blemishes you'll encounter in other large cities (pickpockets, shady currency exchanges, unscrupulous merchants, etc.). Just be sure to exercise reasonable care and you should be fine.

BTW. If given the time and inclination, absolutely make a visit to Pilzen. However, there is the Pilsner Urquell experience bar in Prague that we thought was pretty cool. Also, the Staropramen brewery pub was very nice, and would take euros and dollars at an excellent exchange rate.

Have fun!