The parties must intend that the contract be binding at law. If the parties are not serious about whether the contract can be enforced, then a court will not give effect to its terms because it was never intended to be binding at law. Contracts between close family members can fall into this category in some legal jurisdictions. A contract sets out promises and responsibilities of each party. For contracts to be binding, there must be consideration flowing between the parties.
Consideration means that each party is getting something from the other party.
This can be the exchange of mutual promises to do something or to get something from the other party. For instance, in a contract to buy land, the vendor is promising to sell his or her land and the buyer is promising to purchase the land for a price. In some jurisdictions, legal fictions are used to represent consideration being delivered from one party to the other. In some jurisdictions, this is valuable and sufficient consideration to establish a binding contract. If there is no consideration flowing from one party to another then an enforceable contract is not established in law.