How about making an arena tournament, there will be 3 winers, the arena starts for one day every month, and to make the arena prise fond more interesting, the players that intering the tournament must to bye a ticket to enter, the ticket will cost 100 cobans or 1000000 money (going to the fond as a reward for 1 2 3 places)
Also to make the arena tournament fair on different lvl players, there will be buttons
Join in 100-150 lvl
Join in 151-200 lvl
Join in 201-250 lvl
The same for 300-350 lvls
higher lvl will need a ticket for example 500 cobans or 5000000 money