Houzz is the new way to design your home.
Closet track from home depot to hang barn door.
a sheet of exterior house siding cut to fit the doorway. These sheets are preassembled with tongue and groove joints and are easy to cut to any length and width.
A floor guide from Home Depot keeps the bottom of the door in place. The rubber circular section at the top gently keeps the door from banging around.
The finishing touch to my barn door was actually drawer hardware from Pottery Barn.