In Times Like These: A Time Travel Adventure, by Nathan van Coops, is free right now at Amazon (US -- I'm afraid I don't travel) until May 5. I'm pretty sure this was self-published but it currently shows as being published by Skylighter Press. Skylighter Press, in turn, seems to be a small business in (or near) the author's home town, but does appear to publish work by other authors.
Either way, I've read this book and enthusiastically recommend it!
https://www.amazon.com/Times-Like-Th.../dp/B00FCCT6UQ