I own and control a very small niche... and I decided to write a quick ebook last year explaining a few things. No click bank... just selling it via digital download in my site. A $7 Ebook for 20 pages. Very basic. good info, but basic. I created the ebook in a weekend while watching movies and watching my playing playing in the Garden... After 12 months. I have achieved over 200 sales... so is a no brainer. don't you think?
Another great point. Some of the higher prices you see on CB give the product a weak point. A product will sell better if it's simply cheaper. A $10 product with $10 worth of content will sell better than a $30 product with $30 worth of content. Of course then you run into affiliates not wanting to promote a product because of lower commission. I think article marketing would be the way to go for the cheaper products. PPC wouldn't survive.