The "consideration" requirement for creating a Common Law contract requires that both sides of the agreement give consideration.

The simplest definition of "consideration" is:

"Consideration" is the giving of [1] bargained for [2] legal value.

The definition, obviously has two parts.

The "bargained for" requirement means only that the legal value given is that which the other party requested, i.e. that there has been some communication about who gives or does what for whom. There is seldom, if ever, a problem with that part.

The "legal value" part is somewhat more complex, and is usually the point of disagreements concerning consideration. "Legal value" does not mean that something has a particular market value or that the parties agree on its worth.

"Legal value" is:

To, or to promise to:

Do something the actor had no prior legal duty to do;

OR

To not do something that the actor had a prior legal right to do (or had no prior legal duty to refrain from doing).

NOTE: In this context "legal duty" includes both voluntary and involuntary legal duties, e.g. those imposed by statute, common law, and existing contracts.