Mo. Rev. Stat. § 407.1129: Damages.

1. Damages to the recipient of a commercial electronic mail message sent in violation of sections 407.1120 to 407.1132 are five hundred dollars, or actual damages, whichever is greater.

2. Damages to an interactive computer service resulting from a violation of sections 407.1120 to 407.1132 are one thousand dollars, or actual damages, whichever is greater.