Speaking of whiteboards, how about cleaning them cheaply? I like to either use a 100% water spray (recycled spray bottle) with paper towels, or, I mix a small amount of alcohol in with the water for extra oomph. The alcohol helps dry the board.
If you are really interested in tested methods of cleaning whiteboards, read this.
It beats buying products any old day.
Oh, and if you write by mistake using a permanent pen on a whiteboard–write over it pressing it hard against what was written previously. It really works. I wouldn’t believe it either until I saw it!