Digital copies (and bundles) of all my books can be purchased at my online store: http://shanewsmith.com/store and all books (paperback and digital) can be purchased at my OwnAIndi store: https://ownaindi.com/creator/shane-w-smith/
But if you’d rather go through a reputable retailer, here are some more options.
The Lesser Evil
All The King’s Men
Undad Volume Two
No purchase needed. Read it here for free.