A bank is not going to give you a loan for 2500 bucks without there being any collateral, and I doubt they will finance a vehicle over ten years old. You need to agree on a price and get some paper work with the info on it and then go to your bank or credit union and apply for a loan. Or you can see if the lot has financing available, but make sure the interest rate is low. Some private lots that offer financing tend to deal in high interest loans.