Subject: Re: OT: The ethics of business
So was it ethically questionable to act the way I did – or just being a good businessman?

The only ethics that are applicable here is if anyone was forced to do something they didn't want to do. Remember, in a capitalist system (and all systems are capitalist at their core, at least regarding pricing), the price of anything is what a willing buyer will pay to a willing seller. Were they willing sellers? Of course! Otherwise they wouldn't have sold to you.