A valid contract must contain consideration, which refers to something of value that is exchanged between the parties involved. Consideration can be in the form of money, services, goods, or a promise to do something. It is essentially the reason both parties enter into the contract; without consideration, a contract cannot be legally binding.
This requirement is fundamental in ensuring that both parties have a stake in the agreement and that a legal obligation is established. While contracts can benefit from being in writing, including earnest money, or being a bilateral agreement, these elements do not inherently make a contract valid if consideration is lacking. Therefore, the presence of consideration is a cornerstone of contract validity.