The question is, who decides what is fair?
A transaction doesn't take place unless both sides benefit, you don't buy a gallon of milk for $5,000, that's too expensive. But if you buy a gallon of milk for $4, you are saying that the price is acceptable, otherwise you would not buy it.
Same goes for every other good.
Since what you want is a 'fair market', and the free market is described as the voluntary exchange of goods between individuals, you're going to have to answer who decides what's fair, because it doesn't appear that you want it to be the individuals actually engaging in the transaction.
What we need is fair markets. In fair markets, a government body is established to determine a fair price for every good. Any reseller wanting to jack up prices is revoked from his license to sell things.
The actual result of this is, people will have their license to sell things revoked by their competitiors who lobby the governmental body, causing prices to go up due to lower supply. Licensing is one of the reasons why stuff is expensive in the first place as makes it difficult for supply to meet demand, and those currently engaged in that market do not want new people to enter their market as that would bring prices down.
And what if someone wants to sell below the 'fair' price, which is better for the consumer?
As usual, your attempts to help people will just make things even worse.
I suspect that this person is a troll, by the way.