When I see a drowning child and offer to throw them a life-ring in exchange for their pocket money, they want the life ring more than their pocket money, and I want their pocket money more than the life ring.
Of course you might object that I only have the life ring because I'm the one standing on dry land, but I had to do some work to walk over and pick it up, and you might say that the child had to clean a chimney to earn their pocket money, but that's not my fault. You're just talking folk economics.
Fact is, we both have something of value to the other, so we just exchange, everyone's a winner and we don't need to talk about exploitation.