Is zakat obligatory on a young person's money earned from mobile applications, which is meager (from 1 to 5 Euros daily), and makes him feel independent?

Zakat is obligatory on the proceeds you earn from selling applications, subject to two conditions: reaching the nisab (threshold) and the passing of a hawl (full lunar year). The nisab for paper currencies is the equivalent of 85 grams of gold or 595 grams of silver, and the amount of zakat to be paid is 2.5%. To simplify, you can pay zakat on all your accumulated money after a hawl has passed since you first acquired the nisab, or you can pay zakat on each new sum of money as its individual hawl passes. As for giving charity and spending voluntarily on the poor, it is a religiously desirable act with tremendous benefits.