Mm, depending on how he was pricing things half off for a guaranteed repeat customer daily isn't really that bad of an idea, since it could still be profitable. As popular as his potions are, he probably doesn't get many people who need several of them daily. Even the adventurers or whatnots are probably just stocking up a few at a time for emergencies out in the field rather than just chuggin' the things out there over every little scratch (unless everyone's just addicted to them because they go down so easy and make you feel better, but let's assume people are drinking responsibly). More likely he'll just outright cure her and call it a day anyway though.