Lol, you really think your onto something here? The price increase in coal is not because of f2p making bars using coal. Can you remember recently a new quest came out? It was called rocking out, and it had a level 69 smithing requirement. This is the reason coal has risen, more demand on smithing products, thus increasing the value of the raw material. Coal will drop very soon once the demand for 69 smithing drops, which will be within the next week or so.