"Well, Martha, at least the damn whippersnapper didn't ask what a newspaper is..."

I kid. Back in the day, newspapers made most of their money off of advertising. Full page ads for things like supermarkets, furniture stores, cars, and luxury items. Smaller ads for movies, specialty shops, etc. In fact, you'll see some older newspapers whose name was The Advertiser. The classified ads were 'classified' by the type of ad. There'd be five or six full lenght columns with short ads. Help Wanted and Apartments to rent would have the most spots, but there were plenty of ads for Yard Sales, Handymen, Pets for sale or adoption.

If you read the book, the hero explains why he enjoys reading them. It's a great novel; the author takes most of the tropes and punches them in the crotch.

https://www.warwickadvertiser.com/

Just found this site with a quick search, and it helps because it actually has a classified ads section in the back.