Buying a high mileage car (which is what you will get for under $10k) is a very, very bad move if you can afford to do better.
High mile cars are high risk cars. Most Japanese imports do well with high mileage and repairs, but some do not. As you put miles on the car, you will start throwing good money after bad when you have to make expensive repairs. Eventually, you will be looking at repair bills that are not far from the current FMV for the car.
Dealers do not like to haggle much on high mile cars because they can usually find someone with bad credit who is desperate just to get a deal. They would rather pass you up for someone who is going to give them a big finance reserve and pay asking price. If you buy a high mile car, get one from a friend of a friend or family member you trust. The price will be better and risk lower.
If you have good credit, you can do much better with a new civic of corolla. Use your cash for a down payment and end up with a very small monthly payment. You will have no repair bills the first few years. You will have equity in the vehicle in a few years if you get married and need something bigger or are just making more money and want something better. No matter what, with a high mileage car you are going to have very little market value three years from now. So, what sounds like a deal, might not be.
For example: high mileage car for $9k:
Three years of repair bills will be $1-3k (conservative)
Market value after 3 year=$4,000 (very liberal)
If you want a different car or it dies after 3 years, you will have spent 10-13k and will only get back 4k, max. Net will be 6-9k.
New civic or corolla: 9k down, finance 9k:
Three years of repair bills: Zero.
Market value after 3 years: 12-13k (conservative
Getting out of it after 3 years will be a net of about the same as driving a junker but with no risk and you get a nice new car.