If not for carfax.com, I might have purchased a car that 1) was a rental vehicle; 2) was involved in a collision; and 3) was originally purchased in the Washington DC area (I'm in California). I definitely don't want to buy a rental vehicle, nor do I want to buy a car that was in a collision.
VIN report - not bad for $25.
(I do not work for / am not affiliated with carfax in any way. Just posting information that may be useful to others.)