In the British case Carlill v. Carbolic Smoke Ball Co., the defendant company placed an advertisement in the paper that £100 will be paid to any person who contracts the flu or a cold after having used the ball three times daily for two weeks according to the printed directions supplied with each ball. It is sufficient in the case of a continuing offer that notice of acceptance is supplied at the same time as notice of performance provided that the offer has not been revoked. [...]

In Lucy v. Zehmer both parties signed a contract to sell a farm for $50,000 and gave all outward appearances of assent. The plaintiff relied on that contract and incurred expenses in preparation for the purchase of the land. The defendant could not later claim he was intoxicated and that the plaintiff knew he was insincere. [...]

In Hamer v. Sidway a man promised his nephew $5000 if he abstained from drinking, smoking, and gambling until age 21. The rule is that there must be a benefit or detriment to find consideration. In this case the detriment to the nephew was his circumscribed freedom of action. [...]

In Langer v. Superior Steel Corp., the defendant employer promised to pay a pension if the plaintiff employee would not work for a competitor. The plaintiff accepted the offer and the employer stopped paying. The defendant was bound to pay because it benefited from the plaintiff’s refraining from accepting employment from a competitor. […]