Driving mileage would be the only thing that costs real money in the game, cars, tracks and everything else are free, but still need to be bought with in game credits, would that be too much in terms of real money spending ? Mileage can still be obtained by winning races, completing seasonals, challenges, special events. Mileage will recharge every 12 hours, if someone plays rigorously and consume all those free miles, the bonus miles from the winning can cover it up until to a point it won't, then mileage can be bought with real money from PSN. In order to stay free, keep on winning races, keep the bars filled, or for the lazy - just by more miles with money. It's not perfect, just a simple idea I have after playing the free2play Gundam Battle Op that I got for free from Japan PSN.