joe is thinking about buying jim's bar, two dollar bill's. joe talks to mike to get mike's opinion of what the business is worth. mike and joe decide the bar is worth $500,000. joe tells mike that he will offer jim $500,000 for the business. mike talks to jim and mentions joe's interest in the business and that joe was willing to pay $500,000. jim writes an email to joe that he accepts joe's offer. is there a valid contract?