Dreamworldz

dreamworldz-logoUS $7 per month for a 15,000-prim region on the hypergrid-enabled Dreamworldz grid.

Other region sizes also available, including a 2 by 2 varregion with 25,000 prims for $17 per month, and a 50,000 prim varregion for $28 per month.

More info here.