Mo. Rev. Stat. § 419.040: Rates — duty to post.

It shall be the duty of every lodging establishment in this state to post a written or printed copy of the rates charged for each guest room in each guest room. If a different rate is charged for different rooms in such lodging establishment the rate posted in each room shall be the rate that applies to such room. This section shall not apply to lodging establishments that publish current rates electronically on a public internet platform or that do not have more than ten guests on an average each day.