In terms of valuing option contracts, it is essentially all about determining the probabilities of future price events. The more likely something is to occur, the more expensive an option would be that profits from that event. For instance, a call value goes up as the stock (underlying) goes up. This is the key to understanding the relative value of options.
However, unless soybeans were priced at $15 per bushel in the market on the expiration date, the farmer had either gotten paid more than the prevailing market price or missed out on higher prices. If soybeans were priced at $13 per bushel at expiry, the farmer's $15 hedge would be $2 per bushel higher than the market price for a gain of $2,000,000. On the other hand, if soybeans were trading at $17 per bushel at expiry, the $15 selling price from the contract means the farmer would have missed out on an additional $2 per bushel profit.
The price at which you agree to buy the underlying security via the option is called the "strike price," and the fee you pay for buying that option contract is called the "premium." When determining the strike price, you are betting that the asset (typically a stock) will go up or down in price. The price you are paying for that bet is the premium, which is a percentage of the value of that asset.