What Are the main things to look for in a car when your buying it?

Im about to purchase a Great deal on car, Its a 2007 Scion tc with 44,000 miles on it almost New. I've turned it on and took it for a test drive... it feels and sounds very nice and i also looked under the hood and it looks clean..the oil and air filter looks good!! This car is from a Buy here Pay here so im sure they don't inspect there vehicles, I really need some help on what i need to look for to make sure im not buying a broken down car..please help :)