Have you considered publishing your book via Amazon on Kindle?
Your up-front costs are zero (except for writting the book and formatting it for the Kindle, Of course). You get relatively fair share of the money people pay for your e-book. The e-book is DRM protected(*), so you do not have to worry that people will be sharing it on pirate sites.
The only problem I see will be persuading people to buy your book ;-)
(*) not that I like DRM protected e-books but from your point of view it gives you peace of mind
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