So if you are evaluating an App, it's easy to get sucked into an unwanted subscription. You need to stay on top of those Apps that let you evaluate and then after a time charge you for a subscription. It's a bit tricky to find the cancel subscription setting so follow the link above to see a page like this. It has good instructions.
Fortunately, Apple is pretty good at refunding if you contact them early. Here's a chat response I finally got after cancelling the subscription and asking for a refund. So be sure to ask for a refund if you do not want the App subscription. Apparently takes a while for the refund but at least you can recover.