If you decide to trade it in, they are going to screw you over and you probably be flipped in payments. What I mean by flipped is: You won't get enough money to payoff your loan, therefore the rest of that will be carried over to you new loan, which this case will be a lease. Your payments would be higher than normal.
I am a little sketchy on how old you are, but I'm guessing in the age of 16-19ish(correct me if I am wrong). If your still in high school, don't lease it, just for the main fact that other kids are careless and don't give a sh*t about the car next to them(giving you a nice little door ding). If you have dents or unusual wear to the car(dents, scratches, etc), the dealership will charge you for it. Also, if you ever wanted to mod your car you couldn't, because it would void the warranty, hence you would be subject to overcharge on the lease. Thats enough about leasing.
If you buy a NEW car, you are still under warranty for 36k or more. You can buy an ESP for the car and have it 75k or more. It's YOUR car and you would be able to mod anything on the car you wanted. Remember it's YOUR car, not anyone elses.
I would actually buy a NEW transmission and then drive that to the ground. Our cars have horribly resale value, causing the low trade in value. One other thing before I am done, don't even look at Kelly Blue Book. because the dealership will hardly go by it. It's not worth arguing either, because then they are less likely to deal with you on the car.
Alright, thats enough for now, if you have any questions, ASK!!!!! I did work at a car dealership for a while.