There are some ways to do it for free, none of them really ethical -- at least that I know of. I could do if for you, but I won't. Spend the money. Edmonds or CarFax.
Well, there is a way that is I guess ethical -- find a used car dealer in your town. One of the more downtrodden ones that offer CarFax on the vehicles they sell. See if they will run it for you for $15-$20.