BRR
there is no limit to the amount of karma someone can have. As long as there are bookie events, someone could win a trillion karma. With real money in the real world, additional value has to be created. The current system is the equivalent of allowing people to print their own money, and then acting surprised at rampant inflation.
You have to control the supply and lower interest rates.
(1) Make bookie a separate forum with a separate currency.
(2) Karma tax. The typical graudated tax.
There also has to be a limit on the total karma available. For example, you decide that there will be a karma reserve of say, one billion karma. That is then exchanged among people and increases proportionally to the number of new members or something.
That way, getting into the karma game is easy - you can get 1,000 or 50,000 with ease, but if you want to get 10,000,000, you might have to pay a higher price for it, because there is less to go around.
You could also encourage more members to join.
You can't devalue it now because there is no limit on how much comes into the total