If you want to save money on accomodation I recommend couch surfing. You will find a lot of Romanians registered on http://www.couchsurfing.org/ willing to offer you their livingroom couch. Plus you will see exactly where and how local people live.
For a 4 star hotel room you could pay from 50 to 90 or even 100 EUR per night. 3 star hotels are slightly cheaper with room per night ranging from 35 to 50 EUR. The cheapest acomodation is hostel and you pay around 7 or 8 EUR per bed per night. It’s also worth looking into apartment rental with prices of 30 to 50 EUR a day for a 1 bedroom apartment.