Close to the stairs of Piazza Trilussa Freni e Frizioni is one of my favorite places for an aperitivo (a drink plus ‘all you can eat’-buffet).
Born in 2005 Freni e Frizioni is now a must visit place in the Trastevere zone. Every Roman has been here at least once!
Aperitivo time goes from 19:00 till 22:00 and inside there is a long table filled with many pans focused mainly on vegetarian dishes, such as salads, rice, couscous and legumes. Better go early because it gets crowded easily. If the weather is nice I suggest you try to catch one of the red tables outside.
The place is furnished with many vintage furniture and recycled stuff, if the bar is packed (as it usually is) you will probably end up eating on a petrol bin.
Getting there: Tram 8 stop at Belli or Bus line 280 stop at Trilussa.