No it's not. It is something you will have to pay only near the end of the 4th kingdom. At this time, you must have get at least 5 girls and i think you whould have at least 7 or 9 girl easily. What can you do with the money you get from them ? Maybe you forget to upgrade them (affection) and that's why you don't get any money.

Personnaly i get 70k money each time i connect and 34k per hour with 24 girls (4 of them are event girl so they count only as 2). You also have mission and troll fight which can give you 1k each time.

Maybe you can consider it a high price only if you connect once a day but think about people who connects many times. It will stop your progression as it did for me but next time you will keep money to prevent such a thing (for me it's 500k)