The people of Sumer and the people of Babylon (the civilization that was built on the ruins of Sumer) were divided into four classes - the priests, the upper class, the lower class, and the slaves. We do not know if you could transfer between classes if you got wealthy, or if you were stuck in your class unless you became a priest. Priests were special.
Priests were very powerful and important. They told people how to behave to keep the gods happy. Priests in Sumer (and in Babylon) were also the local doctors. If you got sick, you sent for a priest. The priests shaved their heads so that everyone knew they were priests.
The Upper Class:
Both men and women wore jewelry. Men wore long hair and long beards and wore a skirt type garment. Women wore long dresses with one shoulder bare. In the colder months they all wore cloaks made from wool to keep warm.
The Lower Class:
The working class wore the same type garments as the rich only theirs were not of the same materials. They too wore jewelry although theirs was not made of gold or precious stones.
Sumerians did keep slaves. When they defeated another town or tribe in battle they would bring back the prisoners as slaves. The king and the priests kept most slaves, but wealthy Sumerians could buy slaves to work for them.