<< I agree with Skoorb but I have a different approach.
1) Either borrow $7,500 use $6,000 for the used car use the extra $1,500 towards misc bills, or use it to pay your insurance ahead.
2) Borrow the $7,500 use the $6,000 for the used car send in a payment for $1,500
If you have little or no credit history all I can say is GOOD LUCK! >>
Good ideas - paying well into the future on insurance would be nice - or, since it's used, put it into a repairs account cause you will have repairs.