Edit thought I should say one more thing:
Many write that the cars cost real money. That is so not right. In the beginning you have about 30,000 or 50,000 cash (exactly I do not know more). Of this you can buy one of two cars. Mti said then you drive to earn more money. For certain things (Lvl up, limited events etc) you can earn certificates. With these you can buy some extras, but also certain cars. Sure you can help out with real money, but that is not from my personal point of view necessary. I criticize here also only the misserable update policies Amazon.