Shopping is one of my favorite sports :) I'm not the person to ask if you are looking for a designer handbag or the latest gadget, but if you want to find something food related, I can probably point you towards a place that will have what you are seeking at a good price. San Giovanni di Dio is a stop on both Tram 8 and Bus H which houses a large market for anything food related. This is a semi open market where locals shop for their daily needs, so do not expect anyone to speak English or cater to tourists who want to sample. If you want to experience a slice of the everyday life of Romans, from .50 Euro bargain bins to bring your own container olive oil purchases, this is the place. Walking among the many aisles, you'll find proscuitto,
olives, and their oils,
and local tomatoes.
There are also stands for meat, fish, sundries, and sweets.
The most popular Flea Market is this one on Sundays at Porta Portese, a stop on Tram 8 or Bus 75, with everything that you can imagine from old vinyl records to relics like watch faces your grandparents may have had. There are plenty of hustlers here, so unless you know authentic merchandise very well, do not believe everyone who tells you their brand names are real.
With all the priests and nuns in Rome, sometimes I felt as if I was in a Fellini film, especially seeing so many stores selling robes for the clergy.
My favorite shops, besides the ones selling food, sell natural beauty :)