App? I'm not aware of any app that anyone serious about language learning would consider great. If you are going to pay for an app start with netflix or similar which isn't about language learning, but it has native content in your language. Newspapers would be another place to spend your money.

There are a lot of dead tree books that are still perfectly good. There are a lot of language courses that are great, but most don't really have an app. Even if there is an app, you should be getting the app as part of your purchase (or subscription) to a larger language learning system not the app itself.

something like https://michelthomas.com/landing-page/mt-spanish/#start-span...

or https://www.pimsleur.com/learn-spanish-latin-american/

I would probably include duo lingo when I started - but I wouldn’t say “hmm I wish there was something worse but free”.

I am personally quite happy with the Teach Yourself study materials as first step when picking up a new language.