https://wccftech.com/todays-list-of-paid-games-that-are-free-or-on-sale-at-the-play-store-including-bridge-constructor-medieval-and-more/

The titles are on sale for a limited time only and may go off sale at any moment. Once you download a paid title that’s on sale, it’s yours to keep even after the promotion ends and you can reinstall it on any other device linked with the same Google Play Store ID.

Related Today’s List of Paid Games That Are Free at the Play Store Including CELL 13 and More