Google Adwords
 

The key to lowering the cost of click throughs is with Banner advertising. While this takes a little more time to setup, you can generally hit highly competitive keywords at around 5-15% of what it would cost you for text ads. This is still the same highly targeted traffic as you would get from those text ads. I want to address two concerns you may be having right now: You don't have to have a fancy expensive graphic design studio to make banners - you can download a free graphics design tool called "gimp" that you can design your banners with You don't have to be a graphic design artist - I designed all my banners myself and I have zero training in any artistic discipline, it's simply about getting your message across.