Harlot House, by Gil Brewer (epub/Kindle/pdf)
Prissy Baxter inherited a lot of money when her husband died. She keeps her sister, Liz, on a tight allowance -- but Prissy's will says if Liz is married to Prissy's approval when Prissy dies, then Liz will inherits. However, if Liz is single or married to someone Prissy doens't approve of, then all the money goes to charity... Is it recipe for murder -- or worse?