For a limited time, promotional offers are now available to eligible customers in addition to standard pricing. The Power Apps per app and per user plans are available for USD3 per user/app/month and USD12 per user/month, respectively.
Understanding Power Platform Licensing: Part 1 – Power Apps
Understanding Power Platform licencing is a dark art for some, but in reality its fairly straightforward. The complexity is more often than not to do with choosing the right components to make your solution; do you go Model Driven? Canvas Driven? Teams + Power Apps? There are lots of permutations, and don't get me wrong, licencing is certainly a factor in how you architect a solution.