Early kings of Egypt were not buried in pyramids, instead they were buried in smaller buildings called Mastabas. The word means 'bench'.
Mastabas are mutli-roomed tombs that are built above-ground. THey can be very elaborate and contain many storage rooms and passageways. Mastabas are usually rectangular, with a flat roof and slightly sloping walls. Most were built over a burial shaft to protect the deceased.
These mastabas were originally built of mud-brick and later of stone. Saqqara has many examples of mastaba-tombs, including the largest for Mereruke.
It is easy to see how the mastaba was the inspiration for the pyramids of later egyptian kings. The step pyramid of Djoser, for example, apepars to have started life as a mastaba tomb, upon which another mastaba was stacked, and so one.