The Fast and The Furious/Little Shop of Horrors (1955/1960)
Chosen by me from a list of public domain movies online.
A double bill of Roger Corman goodness.
Fast and the Furious is not particularly great but features some neat looking cars (I'm not really a gearhead but the main car - a jag - is gorgeous), a main character of a female racing car driver and some ropey plot mechanics (i'm still not clear why the escaped prisoner feels the need to go through with the race). I especially enjoyed the reveal of a nebulous truckers union being the real villains (none of them are in it, which makes for some strange dramatic beats).
Little Shop of Horrors is pretty darn terrific. Off beat, irreverant, very funny with a couple of great performances (Jack Nicholson and Dick Miller are a hoot).