Contracts
Formation
Offer, acceptance, consideration, and no applicable defense. An offer must be sufficiently definite; advertisements are generally invitations to deal. Common-law acceptance must mirror the offer; UCC §2-207 lets additional terms in between merchants unless they materially alter the deal or are objected to. Consideration is a bargained-for exchange; promissory estoppel substitutes when injustice is otherwise unavoidable.
UCC versus common law
Article 2 governs transactions in goods. A merchant's firm offer in a signed writing is irrevocable for up to three months without consideration; an option at common law needs consideration. The Statute of Frauds covers marriage, year, land, executor, suretyship, and goods over $500; a merchant's confirmatory memo satisfies it between merchants who do not object within ten days.
Performance and breach
Perfect tender under the UCC allows rejection for any nonconformity; common law requires substantial performance. Anticipatory repudiation excuses the other party, who must mitigate. Conditions are strictly enforced, and every contract carries an implied duty of good faith.
Remedies
Expectation damages put the plaintiff where performance would have; reliance and restitution are alternatives. Foreseeability and mitigation cap recovery; liquidated damages must be reasonable, not a penalty.
Worked example
Buyer contracts for 1,000 widgets at $10 each; seller repudiates before delivery and buyer covers at $13. Damages are $3,000 plus incidental costs, provided the cover was reasonable and prompt.
Rule of thumb: classify the contract as goods or not before applying any doctrine.