In the US, generally speaking, the following items are necessary for a contract: 1. Multiple parties 2. Consideration: all parties must get something out of i

In the US, generally speaking, the following items are necessary for a contract: 1. Multiple parties 2. Consideration: all parties must get something out of it. You may have an agreement where you don't get something out of it, but you cannot have a contract where you get nothing out of it. 3. Offer, acceptance, and mutual assent. One must make the offer, the other(s) must accept, and all have to see eye-to-eye. 4. Legality: you can't make a contract to perform illegal acts. A contract with an assassin is not legally a contract -- one cannot be found in breach of this contract by a court of law no matter what (though bringing the suit may incriminate you for conspiracy to commit murder). 5. Parties legally able to enter contracts. Minors can't enter contracts.