Julie Smith's booksbnimble press, which I consider to be a legitimate publisher, has four free books out for Thanksgiving - free for today and tomorrow per the email I received. At least two of them have been free/on sale before, but two were new to me.
All are first-in-series, presumably to get you started on the series, but many booksbnimble books go on sale/free pretty often, so probably okay if you do get hooked...
Kindred Crimes, Jeri Howard #1, by Janet Dawson
Kindle US:
https://www.amazon.com/dp/B005204Z40
Kindle UK:
https://www.amazon.co.uk/dp/B005204Z40
Murder is a Family Business, Alvarez Family #1, by Heather Haven
Kindle US:
https://www.amazon.com/dp/B00D0B979G
Kindle UK:
https://www.amazon.co.uk/dp/B00D0B979G
The Key to Justice, Marc Kadella #1, by Dennis Carstens
Kindle US:
https://www.amazon.com/dp/B00AC54HI4
Kindle UK:
https://www.amazon.co.uk/dp/B00AC54HI4
Pineapple Lies, Pineapple Port #1, by Amy Vansant
Kindle US:
https://www.amazon.com/dp/B00VV773I8
Kindle UK:
https://www.amazon.co.uk/dp/B00VV773I8