What was Saudi Arabia like in the time of Muhammad?

Answer 1

At time of prophet Muhammad saw that area was known as Arabia or Hejaz, it was renamed Saudi Arabia in 1920.

Arabia in Mohammed's time would have been largely unoccupied (much like today) with the occasional cities dotting the landscape. In the cities, there would have been marketplaces where people would sell wares, shrines for different gods venerated by the different tribes in the city, and numerous militias to defend the different tribes. In larger cities like Mecca and Medina, there would have been places for camels and caravans which would take larger quantities of goods between cities.