Is islamic competition that has fees to participate and has prizes in the end to certain participants, not all, haram in islam?

In my country, there are several Islamic Facebook groups (not fraudulent). Every 2 months or each month, they arrange Islamic quizzes (aqidaah, serah, quran etc.). What they do is set a certain amount of participation fee and give a handful of money as prizes to the participants (first, second, or first 20, 50, or even 100 participants). My question is, Is this competition haram? Is it gambling? I'm confused about its ruling in Islam; please share knowledge on that matter.