I don't have all the figures with me here in London but I think the total cost was roughly 1000 Euros which is about £670 - at most it was a bit over - say £750. That doesn't of course include the cost of the tools I had to buy which I didn't have (cone drills, small hacksaw, set of HSS drill bits etc) as that's got nothing to do with the cost of the amp per se.
Of course I haven't heard it yet but I think you'd struggle to get a decent PWM power amp for less than £1000 new. I could also have economised by not buying the big LC Audio PSU and just rolling my own with a couple of rectifier bridges and some caps, maybe adding in just the the LC Audio soft-start circuit which the sell separately.
Lastly, there's all the fun and pride of doing it all yourself 
Michael.