It Pays to Advertise (1931)

Rodney Martin, with the help of his secretary Mary Grayson and advertising expert Ambrose Peale, becomes a competitor in the soap industry to his father's company. They launch an advertising campaign featuring a soap product called "Thirteen - unlucky for dirt", which becomes wildly successful. However, Rodney does not have the financial resources to actually produce any soap. In order to prevent his competitor, Adams, from acquiring the popular brand, Rodney's father pays him a large sum of money for the "Thirteen" trade mark. During this process, Rodney and Mary fall in love.