In the early Republic? All citizen males wore the toga, and originally all citizen women wore togas as well. The tradition was that originally citizen men had worn no tunic--Cato the Younger was said to have walked around without a tunic underneath his toga, in conspicuous imitation of the early Republicans. So in the early Republic a toga is all that a citizen male would have worn, at least in public. The toga was a formal affair, the dress of the Roman citizen in a public space. It was not worn indoors, and by the later Republic most ordinary citizens (i.e. those not involved in politics or business affairs) probably wouldn't have worn their togas outside of festivals, elections, and other state business. Starting in the late Republic and the early Principate we start to see references to citizens shedding their togas in public for the Greek pallium, which was often a conscious attempt to openly proclaim Greek erudition. But that's much later than the early Republic.

In antiquity the vast majority of clothes were made of wool, though linen might be used as well (especially for tunics). Silk is an innovation much later than the early Republic and would not have been known at all.