I have the HP60 and have had only a few minor problems. I was able to fix them all myself. If you have the right tools, I would take apart the cover and inspect the machine for yourself. See whats loose and I bet with a few parts from HD or Lowes you can make it work right again.
If you want to make a lot of money in this business get a large shop and do production work. You won't be putting out show cars but production shops are not in business to be posting 50/50 shots on 10 forums a day. You will also need to understand that a production operation takes a lot more...
With gas you need a pump. Some electric models have self priming pumps and don't require an external pump. However, most of those models are karchers and if you are spending only a few hundred on it, you are getting a consumer model that won't last very long. I just got the Kranzle K7. Expensive...
You don't need to put conditioner on those seats my man. 99% of leather seats are coated and cannot absorb the conditioner. Just clean them once a month with something mild and you are good to go.