I literally was looking into this last week. I ended up deciding against it. If your walls are like most common walls, you'll notice it's not a smooth surface.

I literally was looking into this last week. I ended up deciding against it. If your walls are like most common walls, you'll notice it's not a smooth surface. That kills it for me. I instead went to Craigslist and found a used whiteboard instead. There were some 4ft by 6ft going for as low as $15 to $30. I ended up picking up a 4ft by 8ft for $70. If you decide to go the paint route, just consider the surface issue.