I think we paid about the equivelent of 100 euro. (off season of course)
We just showed up in Rome one night on our way back from a trip in Tuscany and found this place downtown. It is very close to the Trevi fountain, Coliseum, Spanish steps and Vittorio Emmanuel monument. The staff was very friendly and courteous.
We stopped 50 km befor Rome on the highway on a resting place. There was a stand of the german ADAC. And they recommended us the hotel Bolivar. Itīs near to sigths and worth to advise. You can park your car in front of the hotel.