Actually, not so much. There was some but largely limited advertising in the 19th century, but the start date was February of 1860, when
The Atlantic accepted its first print ad. The practice exploded in the late 19th and early 20th century, with the rise of the factory process and widespread distribution networks, such that goods could be centrally produced and sold in distant markets.
Alexander Holt discussed this in a 1909 lecture, "Commercialism and Journalism", presented at the University of California and published as a small book. It's available on the Internet Archive, and the first section has a considerable overview of advertising practices and statistics:
https://archive.org/stream/commercialismjou00holtuoft#page/n...
Quoting:
In olden times the dailies carried only a very little advertising --- a few legal notices, an appeal for the return of a strayed cow, or a house for sale. It is only within the past fifty years that advertising as a means of bringing together the producer and consumer began. And, curiously enough, the men who first began to appreciate the immense selling-power that lay in the printed advertisment were "makers", or "fakirs", of patent medicines. The beginning of modern advertising is in fact synchronous with the beginnings of the patent-medicine business.
The remainder of the essay is mostly a cautionary exploration of the consequences of commercially-financed press.