How can I obtain information on a vehicle thats for sale?

All I have is the licencse plate number.How can I obtain information on a vehicle thats for sale?
ebmunds.com or kbb.com or carfax ?How can I obtain information on a vehicle thats for sale?
You could leave a phone number on the car under the wiper, just put the number and say you are interested in buying it. The other way is to wait by the car until the owner shows up and tell him/her you are interested in it. If you saw it in a driveway you could just ring the doorbell and ask the person there for the info on the car.
really only info you need to know is what shape its in before you buy it that you can get by typing how to check used car an dyou cant get any info from plate number unless your a cop and it wouldnt have anything to do with car just driver of it if your wanting to buy it then check it for signs of problems easy just follow a check list