What we found that works even better -- and cheaper! -- is to go to your local hardware store and pick up some tileboard (used for doing shower interiors, etc). It's like $5 a sheet and is the same material used in whiteboards! And if you're cheap you can just glue it directly to the wall.
I find that I save a ton of money buying and using items that are marketed for other purposes than I intend. Usually you get the same or better quality without the mark-up. This sounds like no exception.
$13.04 for a 4x8 sheet at Lowes: <a href="http://www.lowes.com/pd_16605-46498-300_0__?productId=301523... 1/8"D x 4'W x 8'H Trifty White Hardboard Wall Panel, Item #: 16605</a>
Or, they also stock a 32"x48" piece ( <a href="http://www.lowes.com/pd_61082-46498-31023248_0__?productId=3... #: 61082</a> ) if you just want one for a cube wall.
Note that this won't be magnetic. The OfficeMax representative said that the magnetic variety was around 3x as expensive as the non-magnetic. Comparing $13.04 to $489, I think I can make that sacrifice.
I'm cheap, but I secured mine to every other stud (32") with some polebarn screws I had on hand (nice white hex head, rubber washer to avoid crushing the hardboard). That way, I just have to spackle and repaint 8 little holes, instead of re-doing the drywall. Cheaper in the long run!
Oh, and it works great as a whiteboard.