Odometer fraud, or tampering, is a violation of federal law, which can result in treble (3X's) damages. You may purchase a car from a "buy here, pay here" lot with acres of used cars and a down payment as low as $50 to $200. You should obtain a CARFAX report for any used car you purchase.
This report can indicate whether the car you are considering has been in a wreck and been rebuilt. It is important to see the title before you buy, so that you know if the person selling you the car has the legal right to sell it.