On vacation to Romania
Passport or id-card
Romania is a part of the EU since 2007, because of that you only need an ID-card to travel to Romania. If you plan on crossing the border with Ukraine you will need a passport.
In Romania they pay with the Leu (plural is Lei). Besides the Leu there are Bani, like we have cents or pennies. A 100 Bani is 1 Lue as you might expect.
At the moment 1 Leu equals about 0,23 Euros (june 2015).
Exchanging for Lei is only possible in Romania itself.