Senders of unsolicited commercial email must pay each recipient a minimum of $500 each under 407.1129 R.S.Mo. if certain conditions are met.
In order recover the $500 recipients must be able to prove that (a) the sender is doing business in Missouri, (b) the sender does not have a previous business or personal relationship with the recipient, and (c) the email does not contain either a return email address or toll-free phone number to remove the recipient's name from the mailing list. For more information see 407.1123 R.S.Mo.
In addition, the statute invokes other provisions contained within the Missouri Merchandising Practices Act, meaning damages may be multiplied by the filing of a class action.