PC - £24.99
Nintendo DS - £23.64
Nintendo Wii -£29.99
PS2 - £24.99
PS3 - £39.98
XBOX360 - £37.00
Official Guide - £9.09
PC - $39.99
Nintendo DS - $29.99
Nintendo Wii - $36.99
PS2 - $29.99
PS3 - $56.99
XBOX360 - $56.99
Official Guide -$13.59
Action Figure - $14.49
PC - £24.99
Nintendo DS - £24.99
Nintendo Wii - £34.99
PS2 - £24.99
PS3 - £39.99 (With Exclusive Artbook)
XBOX360 - £56.99 - (With Exclusive Artbook)
Official Guide -£9.99
Prices may change, so you might want to check the dollar to pound prices, here is the website you can use: http://www.x-rates.com/calculator.html
I have been on several forums and from what I gathered many people liked the PC version more then other platforms, but this depends what type of computer you have.
Most importantly if you are planning to get a XBOX360 you might want to get one very soon because not only does the Play.com version have an exclusive artwork book for it, but the platform has two more mini Tomb Raider games. More info on them could be found here.