The easiest way to beat Cost To State is hitting taxi's and disabling police car's. Taxi's give you 5000-8000(it matters how hard you hit the taxi). When disabling a police car, hit it on it's side while using NOS Stage 2 and/or the speed breaker. When the police car tries to slam you into a wall, turn the opposite way the police car is turning. You'll get 10000-17000(matters how hard you hit the police car when you disable it) box trucks give you 1000-3000, original cars give you 3000-6000, and trucks give you about as much car's get.
When you are in a circuit race and a computer car is next to you force them into a shortcut and make sure they crash doing so. And they will be racing still but they think they are still on the track that they were racing on and they will be stuck there from a minimum of 5 seconds to a whole race isn't that good.
It will work because I have done it several times before.
To get the nissan skyline,subaru,corvette and the charger
Corvette :take the nissan 350z and beat the gold difficulty on the last street cross event (boss race:Hit The Apex)
Nissan Skyline: Take the corvette you won and use it the beat the same race on gold difficulty (boss race:Hit The Apex)
Charger: Take the subaru that you bought and use it to beat all the pro boss races on difficulty
Subaru: Take the charger you won and use it to beat all the pro boss races on difficulty again
The only reason you have to beat all the pro boss races on difficulty is because I forgot which races it is that you get the charger and subaru, but I know that it is on the pro challenges. Sorry if 1 or 2 of these tips don't work
Unlock 1969 Dodge Charger and Subaru Impreza WRX STi: Select the car and correct race level until you are up against the Boss car you want to unlock. Then at the Pro-level Boss races beat it and it and it will be available in your pocket garage.
Unlock Chevrolet Corvette Z06 and Nissan Skyline R34 GTR: Select the car and correct race level until you are up against the Boss car you want to unlock. Then at the Master-level Boss races beat it and it and it will be available in your pocket garage.