For 3K I would definitely buy a new car because for what you get used for 3k you are gonna end up dropping way more money on maintenance and repairs.
You can get a brand new 2010 Hyundai Elantra for 1500 down and then payments of 250ish a month. 10 year/100,000 mile warranty.
You end up with 2k in your pocket, something that will help you build your credit score, a new reliable car with a solid warranty and low risk of any out of pocket expenses that gets great gas mileage.
It's not the "coolest" car, but big difference between people who are successful and those that are not is the ability to make the more financially sound decisions over the emotionally driven "cool" choice.