Actually, economics is easy but it gets harder the deeper you go into it.
Therefore keep it simple and it stays easy. Clutter it up with concepts that sound intelligent and it becomes unintelligible.
Furthermore, the costs of a product are irrelevant to the buyer. All that matters to the buyer is what he is willing to pay. And that is the price or value or worth of a product.
You can apply this sort of approach to almost any facet of life.