A bilateral contract is when both the offeror who is the party proposing the contract and the offeree
who is the person agreeing to or accepting the contract exchanged a promise for a promise. This gives
both parties legal obligations to perform their promises to each other. For example, Mary needed 2
raised beds for her garden and wants to offer neighbor Roger who has experience in building raised
beds. Mary promises to pay Roger $450 in exchanged for his promise to build 2 raised beds by March 1st
and Roger agrees.
A unilateral contract is when only the offeror gives a promise in exchanged for an act of performance
and in return the offeree will receive a reward. This contract is not under any legal obligations towards
the offeree and the offeror may revoke the offer before the job is performed. For example, Roger
replied to Mary’s post of $60 to paint her raised beds. Roger painted the raised beds and Mary reward
him $60 for his performance. However, she may change her mind not to have it paint anymore when
Roger arrive and that would be fine since he have not perform.