Amazon.com has the reprint softcover of Ace with One at $15.95. Also, some used book sellers on Amazon have it as low as $10.26 with $3.49 shipping.
Adrian Smith wrote "
Mick Mannock, Fighter Pilot: Myth, Life & Politics" which was published in 2001 but often runs over $50.
See also
Ira Jones, "King of Air Fighters" which I found in reprint for about $20, and for the autobiographical, Oughton edited "The Personal Diary of Mick Mannock" which looks like it's going for more than I remember ($50+)
Also, there's libraries to try to find copies for reading.
Dan