13.And a bunk bed with stairs and a trundle to get the most bang for your buck. This twin-over-full bunk bed has built-in stairs for easy access and a pull-out trundle for extra sleeping space.

A twin mattress is a smart space-saving solution for many homes, particularly those with children. After all, a standard twin is just 38 inches wide, compared to the 54 inches of a full mattress ...