There are a bunch of games on sale on the Google Play store right now. Some could even be considered RPGs:
Neon Chrome $0.99
https://play.google.com/store/apps/details?id=com.the10tons.neonchrome
9th Dawn II $0.99
https://play.google.com/store/apps/details?id=com.valorware.ninthdawnii
Door Kickers $0.99
https://play.google.com/store/apps/details?id=com.khg.doorkickers
Aralon: Forge and Flame $0.99 (Review)
https://play.google.com/store/apps/details?id=com.crescentmoongames.aralon2
Baldur's Gate II (play this while you buy it) $2.49
https://play.google.com/store/apps/details?id=com.beamdog.baldursgateIIenhancededition
More: https://www.reddit.com/r/googleplaydeals/comments/8tcvnc/games_roundup_of_paid_games_on_summer_sale/
Neon Chrome $0.99
https://play.google.com/store/apps/details?id=com.the10tons.neonchrome
9th Dawn II $0.99
https://play.google.com/store/apps/details?id=com.valorware.ninthdawnii
Door Kickers $0.99
https://play.google.com/store/apps/details?id=com.khg.doorkickers
Aralon: Forge and Flame $0.99 (Review)
https://play.google.com/store/apps/details?id=com.crescentmoongames.aralon2
Baldur's Gate II (play this while you buy it) $2.49
https://play.google.com/store/apps/details?id=com.beamdog.baldursgateIIenhancededition
More: https://www.reddit.com/r/googleplaydeals/comments/8tcvnc/games_roundup_of_paid_games_on_summer_sale/