£37 is nothing for this sim. Remeber, it's not some generic FPS that you'll have completed in 6 hours, it's the most accurate and realistic study sim released to date and it'll keep you busy for months just learning and mastering all the systems.
Let me give you an example, I purchased Falcon 4.0 back in 1998 for £40, I finally uninstalled it from my PC around 4 months ago when I got my hands on A-10C. In those 12 years I'd flown in excess of 3500 hours, now you tell me £40 isn't simply fantastic value for 3500 hours worth of game play.
For a study sim this really is quite well priced, as another example Steel Beasts (a tank sim) will set you back US$120. Study sims will always cost more than your general chart games due to the cost and time required to produce them and the comparatively small customer base compared with FPS games etc.