I spent two weeks in Rome for a travel seminar in college, and it was the best experience of my life. I'm so jealous of you right now! Most expenses we incurred were covered by our tuition, but here are some random things I remember...
- There are water fountains all over the city, and they taste better than bottled water. Carry a reusable bottle and refill when necessary. Your roommate has no idea what he's talking about when it comes to the water! (Plus, some of them have holes at the top, meant of course for you to drink directly from. It's fun when you cover the bottom opening and squirt someone unexpectedly. I only fell for that twice...)
- We did a quick grocery shopping for snacks and such... I only had a 20 euro and I bought about 6 euro worth of goodies, and the check out lady refused to make change. I don't know if it was because I was a dumb American and something was lost in translation, but try to carry small bills with you. Also - get a reusable bag... I THINK (don't remember for sure) they charged us for plastic bags.
- The Metro system was pretty simplistic when I was there. I know they planned on construction, but I don't know if they started yet. The buses were also very easy to navigate (coming from someone who didn't really speak the language and has zero sense of direction). But honestly, the best part of staying in Rome was walking around. It's a very pedestrian friendly city (except when crossing the street into oncoming traffic... whoops...). Of course you'll want to see all of the big name monuments in Rome, and there are plenty of them, but there are plenty of small shops, sights, museums, off the beaten path that you may not find so easily on the internet.
I loved Trastevere. My friends and I still say we'll move to Rome one day, and Trastevere is the place to go. Again, so jealous! Do you have a blog or something to keep track of your travels? I'd love to live vicariously through you!