The Problem arises if one party fails to perform. The trader may fail to sell if the prices of steel goes very high like for example INR 40,000 in January 2017, in that case, he may not be able to sell at INR 31,000. On the other hand, if the buyer goes bankrupt or if the price of steel in January 2017 goes down to INR 20,000 there is an incentive to default. In other words, whichever way the price moves, both the buyer and seller have an incentive to default.
The potential home buyer would benefit from the option of buying or not. Imagine they can buy a call option from the developer to buy the home at say $400,000 at any point in the next three years. Well, they can—you know it as a non-refundable deposit. Naturally, the developer wouldn’t grant such an option for free. The potential home buyer needs to contribute a down-payment to lock in that right.
Arbitrage arguments: When the commodity has plentiful supply then the prices can be very well dictated or influenced by Arbitrage arguments. Arbitrage is basically buying in one market and simultaneously selling in another, profiting from a temporary difference. This is considered riskless profit for the investor/trader. For example, if the price of gold in delhi is INR 30,000 per 10 grams and in Mumbai gold price is INR 35,000 then arbitrageur will purchase gold in Delhi and sell in Mumbai