Two men on a fishing trip pick up a hitchhiker named Emmett Myers, who turns out to be a psychopath who has committed multiple murders. The film is based on the true story of Billy Cook, a psychopathic murderer, and is considered the first film noir directed by a woman, Ida Lupino. I love the feel of old Hollywood crime and this film oozes it. William Talman's performance as the psychotic Emmet Myers is worth way more than the buck you'll pay for this movie gem.
P.S. if you REALLY broke, This film has fallen into the public domain and can be freely downloaded from http://www.archive.org/details/Hitch_Hiker