On average a bollard can be installed by a licensed contractor paying comp and liabilty ins. for about 400.00 ea. This price includes the bollard at a height of 4' above ground and 3' below ground.
This depends heavily on a number of factors.
What type of floor will your shed have:
Dirt - no cost other than time to prepare it. Wood - the cost of lumber multiplied by board foot and dimensions...
For a single hinge or door, most contractors will charge one hour of labor and, if you're far away, likely some travel time. If the contractor has to bring hinges as well, he will charge you...