If there is an agreement between the competitors that each one of them pays an entry fee, in addition to a condition that the winner will receive a prize, then this agreement is prohibited. If the agreement was to pay a specific amount of money to the organizing committee for participating in the tournament, and the organizing committee has control over the collected monies in managing the game, without putting a condition that obligates the committee to give a prize to the winner(s), but the committee gives the prize as a gift without any obligation, then the agreement in this form is permissible.
