£3.98 @ Amazon but you have to pay for delivery under a fiver. If you have an order going anyway though it's worth knowing.
Next cheapest £5.99 @ HMV
Gets very good reviews as a family film/teen comedy.
Sixteen year old Poppy Moore ( Emma Roberts, Nancy Drew ) is a self-obsessed brat, filthy rich and living in LA. After an over the top party goes spectacularly wrong, her father ships her off to an English boarding school to clean up her act. All Poppy wants is to break free and while trying to get expelled the American princess finally meets her match: British girls and teachers that won't tolerate her spoilt ways. Poppy finally realises her bad girl behaviour will only get her so far, so with the help of her new friends and roommates, she sets in motion the ultimate escape plan. Soon discovering that this could be the reason she wants to stay...