Be warned, you'll get free updates for the S2 license - but when S3 comes out it'll be about as useful as an S1 license is now... Which is, er, well, um - imagine owning a Spectrum computer from the 1980's and trying to get a game for it today...
Having said that computer games do represent excellent value for money, time invested versus cost compared to other forms of entertainment is good.
Add to that LFS is cheaper than most games, and yet has a higher replay value because of the online aspect.