I've been using a lot of classified ads like
for just $10 a month I can place as many ads as I want and I convert sales very well from them about 4%, which doesn't sound like a lot until you look at what 4% of 25,000 hits is
and it cost me only 10 bucks a month, some months I place a couple extra feature ads.. to stir up some extra business...
If you aren't using this technique it is worth the time...
I also use PPC with adwords, and likewise for me yahoo just doesn't convert as well.... but I still use it...