I've actually managed to find a website that actually sells the BG series of games. For information only, here is the list of products they sell and the prices:
http://www.gameplay.co.uk
Baldurs Gate 2 and Throne of Bhaal
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Availability: Usually sent within a week
Gameplay Price: £19.99
Baldurs Gate 2 Throne Of Bhaal (Add On)
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Gameplay Price: £17.99 SSP: £19.99 (Save: £2.00)
Baldurs Gate And Tales of The Sword Coast Add-on - White Label
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Gameplay Price: £14.99 SSP: £19.99 (Save: £5.00)
I am only making this post because periodically members of the forum have 'scratched' their CDs and need a new copy of the game. If you know of anywhere else this game can be purchased (cheaper = better) then please feel free to add a post.
Thanks.