ASVAB Prep Plus 2020-2021: 6 Practice Tests + Proven Strategies + Online + Video (Kaplan Test Prep) [amazon.com]
is currently free on Kindle. It looks like it may be for "Army National Hiring Days" (June 30-July 2).
I know my son's school uses the ASVAB as one of their career placement tests, so it's not just for someone joining the Armed Services. The book includes access to Kaplan's online system with extras (videos & practice tests).
It doesn't look like any other e-book shops have the book free (it's $21 at all of them).