I always think it's worth paying a bit more to stay really centrally - like Piazza Navona area or near Trevi Fountain. It is fabulous in Rome but gets tiring and you can pop back to the hotel a couple of times for a siesta, change shoes etc if you are central and you can walk everywhere.
We stayed at hotel Stella just around the corner from the Termini station. it was basic but clean,sheets changed
every day.basic breakfast but ok. Enjoy. ps . look at their
web site.
Gema B&B at Piazza Santa Maria Maggiore, 5mins from Termini station. You can walk with a suitcase or get a cab outside. The train from the airport comes into termini, and it's a huge subway hub. Lots of places close by to walk to, and there is a supermarket RIGHT ACROSS THE ROAD! Was 50 Euros in 2005. www.bedandbreakfastroma.com If you speak to Sergio Ciarlo tell him Rosa from Canada says ciao!