Btw your work is good, and your interface design is particularly good. I and many others would buy your lemonade and not be disappointed, more than I can say for the large amount of stuff on app stores riddled with pay to have fun bullcrap money models. You clearly put time and thought into your work, put some time into thinking about how your work can make money while preserving it's fun and quality and I have a feeling you won't be disappointed anymore.
No donation request = no money.
No in game purchases = no money.
No adds = no money.
All of these together = no money.
Bro you cant put up a free lemonade stand without a tip jar and expect it to replace a job.