it depends on where you get it. either through your bank, or through the dealer. you can ask either for a loan, and if they'll give you one, and how much it is. you don't have to take it.
if your parents are around still, and if they have a better credit score, you can ask them to co sign the loan so you can get a better rate.
while i have a good credit score, i was able to get a better loan with one of my parents co signing, as they had a better score. having a good score, with good history is the key.
just make appointments with your bank or dealer you intend to buy from to get a loan quote.
There's probably o minimum, but a low score will limit the amount you can get, who you can get it from, and your interest rate. Some of the "buy here pay here" lots will finance basically anyone, but for fairly bad cars at ripoff terms for car price and interest rate.
IF you worried about credit slavery score. Buy cash cars and keep ur Money in ur pocket.
Plenty of good cash cars available
It depends on a couple things: how high an interest rate do you want to pay, and how sleazy is the dealer?
My suggestion: Save up and pay cash.
You should not finance a depreciating asset. Save up and pay cash for a good used car.
There are places that will give you a loan with no score at all.