Had a group reivsion session recently for Uni exams with a whiteboard and it went GREAT! So we've decided to get ourselves a whiteboard of our own so we can actually work @ home together rather than in the library! what we've found were ones from Rymans. Not too bad price IMO. Free P+P Over £35. Im planning to get 2 for myself now.
You can also get half cork half white board if you wanted to stick things up. (Same price)
The Quality of them arent overly exquisite (perhaps need another layer of backing card to make it more rigid but other than that it works a charm).
Del. (+£5 P+P i think) or Collection.
Think theres Quidco too :) HTH