There are minigames which earn you in game currency, and they don't use stamina. If you run out of stamina, there’s a variety of things you can do.

Your avatar requires energy to interact with NPCs and you use in-game currency to buy one of 100 gift items.

Gacha Life uses in-game currency and energy. This program is one of the best for anybody interested in learning how animation works or wants to get into animation. Gacha Life: the scratch equivalent for animation