Don't work for free

A bit to late for that . I guess all beginners did that until they felt like they can also earn from it

I'd still understand internships (which is kind of working for free depending on where you are an intern at), but you indeed should not work on a commercial product for free.

I worked for free almost one year during university. I do not regret. I did not care about money. During that year I learned a lot. More than I learned from university. And I learned everything alone.
Nobody teached me. I just needed a project.