Okay, so what you mean when you say "I am buying a human being" is "I am buying something that has value to a human being, in exchange for something that (presumably) has more value to that same human being". I don't disagree with that. But this whole stupid thing started because (primarily) Borachio and Traitorfish were claiming that this is exploitative. It's possible that certain elements of employment are exploitative, or at least undesirable. But fortunately, those same legal fictions that define what "human labour", "purchasing", "selling", etc means also have real actual consequences. Some of those consequences specifically prevent some potential exploitative elements of employment. But if "humans are bought and sold by employers", then employment per se is exploitative. The act of buying and selling humans is inherently and inextricably exploitative. OTOH, if what you're saying is true, and "buying a human" means "informed, consenting adults exchanging something of value to each other", then this isn't necessarily or inherently exploitative. It may be, but it doesn't need to be in order for it to happen.
Now, what El Mac is talking about is (I think) something different. He's not talking about the potentially exploitative aspects of employment. He's talking (I believe) about rent seeking. The exploitation there is of people without access to productive assets by people with exclusive access to them. The latter group (unproductively) seek to exploit the surplus value of the people who use their productive assets without doing anything productive with it themselves. That's a different thing.
Correct me if I'm wrong, El Mac.