Consideration in contract law is the value or benefit given by each party in exchange for the other party’s value or benefit—such as money in exchange for products or services, or mutual promises exchanged. Consideration is often referred to as the bargained-for exchange in which one consideration is exchanged for another consideration.

A mere promise to do or refrain from doing something that lacks consideration in the form of a value or benefit provided by the other party (a return promise) is not a contract and is generally not enforceable. One exception to this rule may be if one party promises to do or refrain from doing something, and the second party relies on that promise to its detriment (by spending money, for example), the detrimental reliance may create an enforceable contract.

And if the consideration for a contract is so insubstantial that it is worthless, the contract is said to be illusory and is not enforceable.

In Wisconsin, as in other states, consideration is a fundamental component of a legally binding contract. Consideration refers to something of value that is exchanged between the parties involved in the contract. This can be money, goods, services, or a promise to act or refrain from acting. The key aspect is that the consideration must be something that the parties have bargained for; it cannot be a gift or an existing obligation. Without this exchange of value, a contract may be deemed unenforceable. However, Wisconsin recognizes the doctrine of promissory estoppel, which means that if one party makes a promise and the other party relies on that promise to their detriment (such as incurring expenses), the promise may be enforceable even without consideration. This is to prevent injustice due to the relying party's reasonable assumption that the promise would be honored. Lastly, if the consideration is so negligible that it can be considered illusory, the contract may be considered non-binding and unenforceable in Wisconsin. This is to ensure that all parties are genuinely committed to the contract and that the contract reflects a true exchange of value.