The Witcher 2 can be had for close to £21 from online retailers, I would prefer to support to GOG directly and buy from them, though.
The Witcher 1+2 works out at £30 if you buy from GOG.com plus you get a free old school cRPG and loads of digital content from Collector's Edition of the Witcher 2.
If you care for the best price around:
Digital Download - Direct2Drive - £20.60 with SIZZLE code.
Retail - the Hut - £21.85 with BHB2 code.
Taken from
http://savygamer.co.uk/?s=witcher&submit=Ok
List of DLCs:
From
http://www.teknylate.com/2011/05/07/witcher-2-day-1-dlc-collectors-edition/
BTW, the guy has an unjustified rant at the Witcher 2's prices but claims them to be much higher than they really are... I agree that DLC content on day 1 is a joke, though.