I want $6000 to get a moto, I'm 17 and earn about $500 a week. Is there a way I can or do I have to wait till I'm 18?

No as you cannot enter into a credit agreement until you are 18.
Just SAVE up..

In 12 weeks , you could do it all by yourself.

I bought a used one when I was young, cost practically nothing, and yes, it did have a few problems. Shop around for a good deal, and learn how to work on one. You need that knowledge even for a new one. Besides, you might have an accident with your first one. $6000 is too much to be spending at 17.