I've listed a variety of Luftwaffe-related titles on eBay, ranging from the highly-sought-after to the exotic to the popular, all at bargain prices. Most have a starting price of just $1.
You'll find the listings at:
http://www.ebay.com/sch/luftkrieg/m.html
Check them out -- it's likely to be worth your while.
Best regards, and a productive, happy and prosperous 2017 to all,
Leon Venter