For fairness, they are in this to make money. To get all the girls and the best equipment you will need money. I speak from experience when I say you can play without money. You will earn more kobans during special events like now. I earned enough for three chances on the last one. Plus once a week if you complete the daily quests you will have another small drop. When you realize the limitations, there shouldn't be any complaints. They are in it to make money and you don't want to part with it, so you will have to accept that not everything will be available to you.