So what if, suppose, that farm owner had some neighbors that weren't fortunate enough to own a farm for whatever reason, let's say they were migrants from a less plentiful place, and decided it would be good for them and himself if he paid them so they wouldn't starve to help him out on his farm. An open market for labor you might say. Would he still be able to sell that produce how he sees fit?
Every single living thing on earth labors under threat of starvation. That's not a shortcoming of any particular economic system, that's a shortcoming of nature, if you can even call it a shortcoming.
He profits from the labor of others. Does he deserve what he gets for it? It's mutually beneficial mind you.
See now you're just avoiding continuing with this line of reasoning because you see where it's headed and it's not good for your ideology. I'm doing a thought experiment here, demonstrating that free markets are in fact incompatible with communist ideas, fundamentally because people cannot be free to sell their own labor on their own terms.