Campo de' Fiori
In the Piazza dei Fiori market stalls are selling fruit, vegetables, fish, meats, household goods, flowers, herbs and so on. It's a very colorfull place.
Every morning (except Sunday) from 07:00 - 13:30 hrs.
It's remarkably how many shops in Rome are selling shirts. You can choose from a variety of colors, fabrics and models. Or maybe you want a tailor-made shirt instead of a standard one? It's all possible.