You can pick up ORIGINAL copies of the latest map disk on ebay - just don't buy a copy as they aren't at all reliable. No really, don't! It may be cheaper but you probably won't be happy with it.

Dealer charges over £200 for one - and they have a habit of trying to get rid of their excess stock of the previous release before they will sell the latest release. You can pick one up on ebay for £70 to £130 - I bought one for £55+p&p - used original 2007-1