I'm not sure if this has been mentioned anywhere, the second of the poolshark-turned-PI series by Robert Fate is free today:
Baby Shark's Beaumont Blues and the first one (
Baby Shark) which was free last week is only $1.99 if you missed it, or it should be available as a borrow for Prime members. Some of the books were nominated for an Anthony and have Pub Weekly and Booklist reviews that sound pretty good. He's got a summer release of the 5th in the series planned and seems to be giving away the earlier books on a weekly schedule as a promo using KDP Select.