Well, actually these don't really go for £250, thats just what some shops ask for them. If you check Ebay they usually go for around £15.
One shop started selling it for that much and other shops followed. It can't be worth that much if you take into account it was in shops all over Europe for a couple of months. I bought my copy when it was in stores and have seen a lot of them since.
If you don't believe me, try selling it to a shop like eil.com for - say - £100.
Well good luck selling it anyway, but I'm afraid it won't make you very rich.