Got started about 3 years ago on it. The first year I only made 300 dollars, second year was 1700 dollars, this year I am tracking to make around 18,500 on that one site alone. We will see...

All my content is offered for free and I get my revenue through several publisher networks (adsense, infolinks, amazon associates).

I used to work at a car dealership so it inspired me to make the site. I've shown my techniques off to a couple of my friends (one of them even copied me and made his own site which was a mirror of mine, suffice to say he does not rank well in google)

The best bit of advice when making a website is to make it about something that you enjoy or know a lot about. It will be easier that way. Sounds cliche but its true.