An agreement to do something or pay something can become binding upon you if the other party acts to his or her detriment upon your promise or agreement to perform, even though they pay or give nothing in exchange. Certain types of contracts are required by law to be in writing in order to be enforceable. Contrary to what many people believe, there is no automatic right to cancel a valid contract, even if done within 3 days. In order to cancel such a contract, you must give written notice of cancellation to the seller within 3 business days of your signing the cotnract. A lawyer will be able to tell you if a particular contract comes with such a right to cancel.
Consideration is the legal word used to denote a valuable good, service, or payment.
Written contracts are almost always preferable to verbal contracts because a written document eliminates disputes about the terms and conditions of the contract or agreement. However, even written contracts can be not specific enough, might not contain language necessary to make them enforceable, or can be subject to more than one interpretation. Contracts and agreements often have significant financial effects to the persons signing them. If a party wants a judge to enforce a contract, the party is required by law to file the lawsuit within usually five years of the date the contract was made. However, the deadline for filing suit may be as little as one year after the agreement was made.