The UK based book seller Naval & Military Press is offering the 3 volume illustrated history of 303 [Polish] Squadron for just
£19.99 for the whole set (plus postage). The actual publisher (Wing Leader) also has this 3 volume set on a discounted sale but they are charging £60 for the set.
From the sales ad:
A superbly illustrated series of three books illustrating 303 Squadron, one of the most famous fighter squadrons in history. With nearly 200 pages per volume, packed full of original wartime photos, fact boxes and biographies. A great modern squadron history. Published at £75 we have the full three volume set at an unrepeatable £19.99 Much has been written about the success of 303 Squadron in the Battle of Britain, but the entire history of the unit deserves description, not just those few glorious months of 1940. During the Battle of Britain, 303 Squadron was an elite unit in the most exact sense of the term, being formed almost entirely of well-trained and combat-experienced pilots and ground crews.
http://www.naval-military-press.com/...e-volumes.html