I think there could be an option for subscribers.
Subscribers get a pick of equipment, and infinite number of good balls a month. You could have gold, silver, and bronze levels -inked to equipment.
Still keep the free game with surveys and videos, and still keep it free for those that win/earn enough credits to play comfortably.
I'd just say that subscribers can't gift - only earned, free or paid for credits can gift.
I wouldn't be immune to paying a subscription fee. Especially if it leads to us getting a second full 18 course every year. Subscribers could get the bonus of being ad free as well.