This is a linkpost for http://benjaminrosshoffman.com/costs-are-not-benefits/
You seem to be demolishing some straw.
The example of needing toothpaste and buying shampoo because it also costs $5 is ridiculous and is understood by all to be ridiculous. I don't really see the need for multiple paragraphs explaining the difference between personal value and market value.
Econ 101 will agree with you that the equilibrium price is the cost of production plus some minimal profit. It might point out, though, that given the difference between the fixed and variable costs the scale of production matters.
What is the non-straw position that you are arguing against?
I was arguing against both the subjective theory of value, and the failure of modern economists to utilize the concepts of use-value and exchange-value as separate things.