These overhead storage racks manufactured by MonsterRAX.com and SafeRacks.com come in various sizes - 4x8, 3x8, 2x8, 4x6, 3x6, 2x6, 4x4 with the 4x8 size being the most popular rack sold by far.
 
Colors available are White & Hammertone

By adding one 4x8 hung 24" down off ceiling is like adding an entire closet.

Are you paying for a monthly storage unit? Use the space you are currently not. You may be able to do away with that monthly recurring bill. Now wouldn't that be nice! 

The rack picture below is storing hurricane shutters.