A list of businesses that "print money" -- mostly cash dealing

[FastPlaySlow]

I've come to believe that the best businesses are ones that virtually "print money".

Why? They don't have to waste any space carrying dead inventory. Money never goes "out of fashion", or so that Perfect Business essay I read from the Mr. Now thread said.

So here are some of the businesses that I believe "print money":

-Check cashing businesses
-Insurance agencies
-Banks
-Stock brokers
-Prosper.com
-Ebay
-Paypal (bank?)

Most of the above cost a lot of money to start up and back up.

Here are some that don't:

-Cardrunners
-Selling e-books

I think the closer we come to having businesses like these, the better off we are.

Can you think of any more businesses that virtually print money?