You take this little guy in a vehicle through various courses and gain gold coins, which you can use to buy more vehicles and courses. I highly recommend the moon course. Even I, who sucks at games like this one, can rack up a lot of coins on the moon level.
I will warn you, this game is addicting. Also, I highly recommend paying for the game once you tried it. The ads got in the way of my stats, etc. Although, the ads do not hamper game play.
however, you can buy almost anything if you save up enough coins. There’s a lot of games out there that reel you in and then want more and more money so you can level up or move on. I realize developers need to be paid, but it’s annoying to have to keep paying to play. So, kudos, Fingersoft.