I hesitate to call Potion Tales a shop sim or retail management game, because the economics of running a figuratively and literally underground magic potion shop seems a secondary concern next to making the potions and deciding whether you want to screw people over or not. If the answer to that last part is yes, you need to move on to the question of how.
In practice, Potion Tales is a 3D puzzle game. People come to you - I use the term people broadly because the tutorial level involves helping a fire spirit and soon after you're approached by what appears to be an aggressive daisy who is the local gravekeeper - and present you with a problem. They ask for a potion to solve the problem. That's all the steer you get. It takes some getting used to, but the Steam demo shows an impressively flexible game with a good sense of humour.