I've been looking for a solution for a computer desk for the longest time. I was looking for something simple, narrow in depth but long in width, and cheap. I picked up the folding closet door below for $5.00 at Habitat Restore.
I applied two coats of paint on one panel after disconnecting the doors.
My favorite handyman attached three sturdy brackets to the studs.
And I now have the desk that I've always wanted. Including the cost of the brackets and paint, the project totaled just under $30.00.