What is the difference between a future good and a contingent good? Can a man/woman buy and sell goods to herself? If so, why? If not, why not? What are the differences, if any, between a sale and an agreement to sell? Can a man/woman buy and sell goods to herself? If the buyer and seller have an agreement whereby the seller would send the goods to the buyer, but no time has been fixed as to when the seller must send the goods to the buyer what is the time frame by which the seller ought to send the goods to the buyer?