I got this idea from the betting from GTA online missions, if anyone has done those. I think the general idea for this plugin is before the game starts every bets $20 on the player they think will win. If the player they bet on wins, they keep the money. If the player they bet on loses, their $20 go to the winner. Not sure how well that will work in terms of the winner winning money or the economy of the game though. Maths is not my forte.
@Sprindex What plugin do you have for the missions? It would be better to suggest it rather than getting another plugin to try to hook into it as the mission plugin may not have an api