Well there are a few ways.(Heres one way) You say your starting a tournament and the prize is say a Kolos. Then you say the price to pay is 500clintz. You sell them a card for 500+price of card they can sell it back or keep w/e. Then your organize them if they all play in different time zones. It makes it easy if you ask for that info (IE timezones). The reason you ask for 500clintz buy in is so if you don't have the card you could buy it, or so you at least make some clintz. You will also want to set limits, like only type 1 or no elo banned cards. You can say we will not start until 10people have decided to join. There you go.