Want to read the original Black Bat stories on the cheap? An account named My Books And Magazines on Etsy offers an easy method by which to do so.
17 BBD books, each scanned as a pdf file. The entire issue is scanned, not just the Black Bat material, so you get the various other stories that were included in the original magazine, the art, the advertisements, letters to the editor, the whole deal.
Of course, you also get the occasional page tear, smudge, etc. I haven't come across any such flaw that affects the ability to enjoy the story, however.
The first book in the collection is The Black Bat Strikes Again, the third in the original series. Sadly, the bundle does not include Brand of The Black Bat, the character's first appearance, but that one should be easy enough to track down in some format or other separately.
The last offering (chronologically) is technically the final Black Bat story as well, entitled Hot, Willing, and Deadly, however I believe that is strictly a Tony Quinn mystery and that he never appears as the Black Bat as such.
Applying that criteria, the final Black Bat story would be The Killer Who Wasn't, and it is included in the collection.
It should be noted that not counting HW&D, three of the remaining stories were not written by Black Bat creator Norman Daniels. Those tend to be inconsistent with Daniels' work and, in my opinion, of lesser quality.
All told, this is an excellent, inexpensive way to sample the character's adventures throughout his original publishing period. Have a look around, a great many other pulp novels are offered in the format as well. Click on the image above to be taken to the page in question.