Many of Rome's cheaper hotels can be found in the streets around Termini station, making them very convenient to reach for the tired traveller.
Rooms can be found for little more than €40, or less if you don't mind sharing a bathroom. There is usually a breakfast buffet available, and it's worth asking whether or not this is included in the price of the room. (Some hotels charge extra for breakfast only if you don't have a private bathroom, so if you're going to be taking advantage of the morning buffet, it might be worth paying the extra for the ensuite. This varies from hotel to hotel, so check the situation when you book.)
If you're on a tight budget, and feeling adventurous, you might also want to look into staying in a hostel.
Recommended Budget Hotels
Via Palestro 55
Tel: +39 06 491057
Just to the north of Termini, Hotel Cervia is basic but friendly and comfortable.
Ho(s)tel des Artistes
Via Villafranca, 20
Tel (+39) 06 4454 365
www.hoteldesartistes.com for hotel rooms
www.hostelrome.com for hostel rooms
Hotel des Artistes is family run, offering hostel accommodation and a selection of nicer rooms. Their site also offers a "name your price" offer for last-minute bookings on the hotel side.
Via Principe Amedeo, 76
Tel (+39) 06 4740 100
Clean, basic and cheap accommodation near Termini station.