14 Philip K. Dick books went on sale once before for $1.99 at amazon, and four of them appear to be back at that price today:
A Scanner Darkly
The Man in the High Castle
The Three Stigmata of Palmer Eldritch
The Exegesis of Philip K. Dick
Note: there's also book called "The Best of Philip K. Dick" showing at $1.99 but it's not a real "best of"--it's simply public domain works.
I checked couple and these do not appear to be on sale in the UK.