this is all done on paper. when u first start off, you write down 60,000 on a piece of paper. then as you purchase a car, and mods, you subtract the credits from your initial 60k.
when you win a race, SR posts how many credits u win. u then add that number to your balance (60k-car-price of mods+ prize credits).
when we did the preseason betting...it worked like this. 5 of us bet 200 credits each. the winner added 1000 credits (200 x 5) to their balance. each loser subtraced the 200 that they lost.
understand now?