If you are looking for a larger region, then a 2x2 or 3x3 may be the ideal option for you. 2x2 regions measure 512 meters x 512 meters or a 3x3 region measures 768 meters x 768 meters of land. The default starter prim package for either of these regions is a huge 40,000 prims.
At checkout there are options for you to custom your region with the following options:
Region Size, Number of Extra Prims, Water or Flat Land and Number of Concurrent visitors at any one time (Traffic)
A standard region is a "full sim". A 1x1 region is a 256 meter by 256 meter piece of virtual land that comes with a huge 16,000 prim allowance for you do build with. You may buy any number of standard regions and place them side by side to create a larger area (your estate).
At checkout there are options for you to custom your region with the following options:
Number of Extra Prims, Water or Flat Land and Number of Concurrent visitors at any one time (Traffic)