Before buying!

It is up to you the buyer to make sure the car is up to standards but a few things to remember before buying any vehicle:
Its easy to make a simple mistake to later find yourself in jail such as a friend of mine did not too long ago... All because of
complications in registration/plates.

Verify the car is the sellers.
Verify that the VIN is correct on paper.
Sellers information is all acurate and correct.
Do a Lein check on the vehicle for any outstanding owings on the car.
If the deal seems completely off the book value, be cautious!
Have a Government inspection done on the vehicle. You could find yourself with either a simple fix-it ticket (or) impounded with a MVI ticket.

Other simple checks before buying/driving off...

Inspect that all headlights, tail lights, signals and markers are not busted up and that they are working properly.
Take the car for a test drive both in city limits and on the highway.
Make sure that both front and rear plates are mounted to the vehicle, unmodified & decals showing as they should.