Yes. Fishing App is free on the App Store and has no in-app purchases.
Paid subscriptions are not currently offered in the app. If that changes, the price and the terms will be shown in the app before any purchase — nothing is charged without your confirmation in the App Store.
I see a charge I do not recognise
Fishing App does not charge you today. Check the purchase history of your Apple ID first — the charge may belong to another app. If it does name Fishing App, write to us at support@blacklabr.com or in the chat on https://blacklabr.com and ask for a person from our team.
The full rules are in the Terms & Conditions.