The example is ridiculous. There's NO SUCH THING as a 10% interest savings account or a $100/mth car payment. There are other economic factors involved that are totally ignored here - you think you're going to buy a $6000 car and drive it for seven years without paying out a crapload of money in maintenance? C'mon! Most cars are designed to last not much more than 7-8 years in the first place, and it's gonna be 5-10 years old before you can pick it up for $6000.
There's no such thing as a free car, and this example doesn't show anything ending up "free". It just shows that you're ahead of the game if you sink less money into your car and are disciplined about saving. Well DUH.

I wonder how much I could make publishing my "live for free" plan. Say you're spending $200/mth on groceries - just cut your grocery bill to $70/mth and put the other $130/mth into a savings account that yeilds 10%. Presto!

What's that - your mortgage is $1000/mth? Well, here's the solution - move into a place that's $350/mth and put the remaining $650/mth into that same 10% savings account. Whee! This is easy!