You can purchase LAND in official The Sandbox LAND sales, which are held on the Map of The Sandbox website. LAND can also be purchased second-hand.
A single 1×1 plot is 96 meters wide, 96 meters long, and 128 meters in height. In The Sandbox’s metaverse, 1 meter is the equivalent of 32x32x32 voxels
A standard playable avatar is 2 meters (64 voxels) tall.