Both anthropologists and archaeologists are still reconstructing the ancient Mayan culture, including the social order. Currently, different theories (also called models) exist as to what things were like. One thing that they know is that ancient Mayan culture --including its social order -- changed by region, and also changed over time.
One theory about how the ancient Mayan society was generally structured goes like this: in the ancient Mayan world, people lived in city-states, where one city controlled a region. Kings were at the top of society, and under them were the nobles, the scribes and the priests. Underneath the nobles, scribes and priests were the merchants as well as artists. The next level down on the social pyramid included the commoners (such as farmers) and the slaves. This last level was possibly the largest, and worked for the upper levels of the social pyramid. This system was thought to have begun around 300 BC, and grew more elaborate by the Classic Period (around 200 AD to 900 AD).
There is an argument that says the social pyramid was not rigid. In this version of the theory, farmers had some control over things because they controlled food production. At the site of Ceren, archaeologists found that people seemed to have extra parts for things, and may have actually had home businesses selling items.
"The Ancient Maya" sixth edition; Robert J. Sharer, Loa P. Traxler; 2006
Illinois State University: Archaeology, Political Economy and the Maya Commoner