Another option for advertising is media buying or ezine
Media buying means buying adspace through specialized
advertising companies. You can often get better deals
than in Adwords.
In ezine advertising you are using to your advantage
a fact that someone already has a list of buyers who
trust his advice and therefore you can often get high
click through rates for your ads - more people end
up buying your product.
The trick is how to choose the correct advertisers and
what to offer to get a sale. See also the free ebook on
ezine advertising for some more info.