I have researched both "Motor Millions" and "Think A Little Different" by Dean Graziosi, and I would not consider either to be a serious income producer. "Motor Millions" talks about how much money you can make, buying and selling cars at auctions.  I was surprised to find out that it was well put together and some of the info was actually pretty good. A person could use this info to make a bit of cash getting involved in the car game. 

Dean Graziosi's "Think a Little Different" course is mostly a motivational pep-talk, in my opinion. Dean's manuals for $35.95 include, Personal Secrets to Real Estate Millions, the Truth about Making a Fortune with Tax Sales, Buying Foreclosures and Liens made Easy, and True Secrets to Buying with No Money Down.  If "Think a Little Different" were written in a step-by-step fashion that will truly help you make money, I might have been more impressed.

Thousands of books have been written on the topic of motivation, and it seems Dean Graziosi has read some. So have I, and I think maybe the same ones! Most of the info in the book seemed like recycled material that I've heard before. I really felt nothing new was offered.  However, if you're new to Marketing, you may find something useful there.