How much does the band app cost?

Excuse me, I was wondering if you could tell me a bit more about the pricing for the band app. Specifically, I'm curious about how much it costs to use the app and if there are any additional fees or charges that I should be aware of. Is the cost a one-time fee, or is it a recurring subscription? Additionally, are there any discounts or promotions available for new users or for those who refer friends to the app? I'd appreciate any information you can provide to help me make an informed decision about whether or not to use the band app.