What do they use in Prague and Budapest? Do they take Euros or must I exchange each countries' currencies?
I don't know about Budapest, but the Czech Republic has its own currency. There are web sites that can tell you. Try Google.
In Hungary the currency is Forint.
Euros probably will be accepted, however legally they don't have to, it's not their currency
many many many of us on the message boards, love to help our fellow travelers.
However, it is important for YOU to do your homework too..
This question could have been googled with a result for both in 7 seconds.
or you could have looked it up in the Rick Steves book
or you could have searched xe.com and oanda.com
Prague uses the Krone. $1 buys 16 Krones. The exchange rate is very good right now! You have nothing to worry about.
You can use euros in prague, but many local places only take crowns.
budapest forints or euros. you can exchange youir own currency their. exchange rates are good and no service charges.