This book has made me some money. Quite a lot in fact but it is still a good example of the "how and where to publish" dilemma.
Proper publishers were not interested so it had to be self-publishing.
Paper based pubilshing was expensive on toner and paper and postage/packing costs ate into the profits.
An electronic version (*.doc) via Ebay was workable but the balance of proof established by Paypal means that any buyer who chooses to claim non-receipt gets a refund regardless.
PDF files are harder to edit and so harder for the bad guys to pass off as their own work. Both Ebay and downloadable from a web site versions were created but both with the Paypal problem
The Kindle version has just become available - so the jury is still out on that one.