Is monthly subscription Haram For Tournament

If I arrange many halal games tournament by taking only monthly subscription then will it be a haram project. In that case, user will pay only a monthly subscription fees like $1 for whole month. then he will join all the tournaments for that month. If he wins a tournament then he will be rewarded with some cash according to that particular tournament reward money. If he loose then he will not get any prize and he will not loose anything else. We will take only monthly subscription fees and except that user will not provide any fees. So is it a haram project? Thanks in advanced