Help... Printer app Airprint is going to charge me 50$ and it doesn't work for me.

Find out which app it is and then contact its support team and ask them about the charge and to cancel it. That is the best route to take. If that does not work then you may start here ➔ Refunds, Subscriptions & Billing Questions

Axel F.

It has a free trial, and if you cancel the subscription during the trial you should not be charged. Go to Settings, tap on your name at the top of the page, then Subscriptions. Tap on the subscription and cancel it. If you were charged you can request a refund→Request a refund for apps or content that you bought from Apple - Apple Support

And you really don’t need any app to use AirPrint; it’s built into the phone.

Ok. Then please start here ➔ Refunds, Subscriptions & Billing Questions

Axel F.

Search where you downloaded it in the App Store. There will be developer info there.