In the business of selling words, sounds were the first to be sold. The ancient sophists sold sounds for orators to persuade, for politicians to collect votes. Before the rulebooks were written, professional wordsmiths had invented the game of speechifying the social and political landscape. It only worked in a democratic, or at least superficially democratic bubble, so ancient Greece won the palm for getting there first.
The sophists took payment for education and rhetorical skills and targeted the wealthiest rungs of society. They provided Europe’s earliest masterclasses.
The selling of words continued after the ancient period and become remonetised as prayers for donors in this life with a view towards investment in the next. Monks prayed for families and individuals who provided for the monastic institutions. Donations and endowments were converted into sounds lifted up to heaven.
By the time Tetzel and his holy salesmen were driving Martin Luther up the (cathedral) wall, sounds and words had been sold in various ways.
We keep selling words for promise, profit or comfort. And we keep buying, creating ever more demand for them.