ran into a bug that im not sure how to explain... while training the girls the game takes way to much money I had like 40k saved up and went to go do a dungeon on i had -144 that hurt me lol
Ah, I see. The cost is 500*(1 + [stat points above 9]^2). But when forcing you to pay, it does so after training the stat, so you're paying as if you're training a stat higher.