Video Editor with custom effect masking and shape/drawing overlays
That isn't really rotoscoping, just mask drawing.  Rotoscoping is more on a frame by frame basis generally.  Either way, After Effects will do what you are looking for very easily, but is not in your price range (not even nearly).  Largely, you get what you pay for though and I'm not sure that there are a whole lot of cheaper options that allow you to draw your masks in the editor.