D grows, and P buys and resells, millet, a grain used for, among other things, birdfeed. D and P have transacted business in the past on numerous occasions. On May 30, 2002, they discussed a forward contract for 15,000 bushels of millet. D wanted $5 per hundredweight. P said that price was not then available. Even so, four days later, relying on D's offer, P sold the millet to a buyer at a rate sufficient to meet D's price. P tried to reach D by telephone to inform him of the sale. On June 27, 2002, P spoke with D and mailed him a written and signed purchase contract. D did not check his mail and never signed or returned the purchase contract. At harvest, the market price of millet had trebled. D delivered to a grain operator in Paoli. P sued D for monetary damages, based on claims of breach of contract, promissory estoppel, and unjust enrichment. The trial court held that D had entered into and breached an enforceable contract to sell 15,000 bushels of millet at $5 per hundredweight of product and P was entitled to recover $82,500 in damages. D appealed. D asserts that under 2-101 he could not be bound to a contract based only on his oral offer to sell; that P's contracting to sell the millet to a third party did not constitute an acceptance of his offer; and if a contract was entered into, it was not enforceable because it was not in writing and signed by both parties.