Summarize:

Most car dealerships have a subscription account with Carfax that allows them to provide you with free Carfax reports on all their used vehicles for sale.  Contact the car dealership before you visit their salesroom to verify that they provide free Carfax reports. Ask a representative from the car dealership for a free Carfax report on the vehicle you are considering to buy. Many car dealerships will provide direct links to free Carfax reports on their websites. Access the section of the car dealership's website that features used cars. In most cases, links for free Carfax reports will be embedded onto the website next to descriptions and pictures of used cars for sale.
Obtain a free Carfax report from the car dealership. View a Carfax report online at the dealership's website.