My wife and I had a great stay at Matteo's flat. The bed was comfy, there's a washing machine, and he left us plenty of ingredients in the pantry.
We didn't actually meet Matteo, it was his friend Angelica who let us in and explained everything.
The flat is in a very diverse neighborhood, which means great-cheap food, especially if you want something beside Italian. Lots of good indian and Chinese restaurants nearby. We walked everywhere, except the Vatican, we took the metro there. Just hop on at Termini, it's a straight shot.