If its so evil, then there's evil in every corner of life.
Business is what made this world what it is, and business is what keeps it running.
Could it not be argued that greed and desire is what pushes us to take a step further into productivity and development?
Isn't it why we hire certain people to sell things for us at a higher price?
I'm not trying to say what happened to the OP was not a very jerkish thing to do, but I'm just trying to stand on the other side of the argument here.
The world runs on everyone trying to scam each other out of their money. And if you're the only one playing the nice guy, you'll be left behind. This doesn't mean you should run around and scam everyone. It means you need to keep a perceptive eye, grab good deals whenever there is one to be found, snatch every opportunity.
What you're all speaking of is equivalency, something that is only written in books for ideals.