You can get much farther with a kind word and a gun than you can with a kind word alone - Al Capone
The "Home" version is listed at £89.99 quid for the Upgrade version, and £179.99 quid for the new licence. The "PRO" Edition is listed at £179.99 for the Upgrade, and a whopping £269.99 quid for the new licence.
This is what Win XP "N" looks like, in theory.
Amazon UK's listings
You might like to note that for the £269.99 you'd fork out for one WinXP Pro N licence, you could instead buy not one but two copies of Linux - for instance, a copy of SUSE Linux Pro 9.3 ( £58.49), and one copy of Linspire 5.0 ( £36.97).
After that, you would still have money to buy one quality Office Suite like Sun's StarOffice 7.0 (for Linux and Windows on the same CD allowing you to install it on up to five systems, legally) for £33.99, and a copy of Wordperfect Office 2000 for Linux ( £50). And still have plenty of money left to purchase some assorted Linux Games.
Also, the price of Windows XP Pro N can get you two plane tickets from London to Luxembourg so you can visit some Eurocrats and let them know what you think about the effectiveness of the non-mandatory nature of Europa's antitrust action against the Vole. µ