Matt offers to pay Lisa $1,000 if she will paint his house, insisting that the acceptance occur only by the act of painting the house rather than through Lisa's promise

Finance Dec 24, 2021

Matt offers to pay Lisa $1,000 if she will paint his house, insisting that the acceptance occur only by the act of painting the house rather than through Lisa's promise. Lisa thereafter begins to paint the house. Matt then attempts to revoke the offer after Lisa is approximately half way through painting the house. Assuming there is a valid contract, what can Lisa recover as damages, and why?