Inexpensive and cheap Eastern European country to travel that offers a lot to see?

I am probably staying in a hotel. I am on a very, very small budget so I need cheap attractions, cheap food, cheap and good public transportation, and cheap accommodations. I am also looking for a city with a lot to see and do. (And fairly safe)

Thank you
Please expand on your answer! Thank you!
I am not just looking for a Eastern European country. It can be anywhere in Europe as long as it's not expensive