Historians have been arguing for the last hundred years about how the Roman economy worked. There are a lot of different possibilities, but the two main ideas are these:
Many people think that the Romans had a very simple economy. Most people were farmers, who ate mainly the food they grew themselves.
They made most of what they needed themselves, clothes and furniture and tools, and rarely went to a store or a market.
They didn't sell much either. Every few months, though, tax collectors would come and take some of the food the farmers had grown. The tax collectors would take this food to the cities, to feed the aristocrats and their slaves there, and they would send some of it on to feed the soldiers in the army, and some of it to Rome to feed the Emperor and his court, and the people of Rome. This is sometimes called the "consumer city" model. If this is true, we might expect that people would also live in very simple houses (the kind they could build themselves) and use very simple tools.
These are both extreme views, and many historians take a position somewhere in between, saying that farmers ate some of the food they grew, and made some of their own clothes, but they also sold some food and bought some stuff. Thanks to new studies, and especially to archaeological excavations of Roman farms and Roman cities, the situation is gradually becoming clearer.
Even very poor farmers owned things which had to be bought in stores like this glass bowl.