I think a call to the council could be a wise move - after all, if you pay someone a fiver and they dump them on the street, are there any implications back to you for littering etc?
Someone you know or you will know a teenager who could do with some extra cash. To be honest though as a means of advertising leaflets aren't that effective. I know someone who advertised an over thirties nite with 50000 leaflets in the local free papers, 1 person turned up.
Depending what your business is I would take out a small ad in the local free paper, advertise on the net on "local" sites (free most of the time) etc etc