As I recall it was on the order of about 1/5 a typical annual income.
This being in the late 18th century, 300 years after Gutenberg, with a well-established printing trade.
Books remained staggeringly expensive.
The progress made in printing over the course of the 19th century boggles the mind. As of 1800, typical presses were still made of wood, and though printing was generally in quarto or octavo pages (4-8 impressions per side of paper), a pressman might turn out 120 - 180 impressions an hour, and I believe that's generous.
The improvements from there were:
- Cast-iron rather than steel presses. Greater strength, lighter weight, improved efficiency and mechanism. Print rates doubled.
- Steam-powered presses. The pressman no longer was responsible for physically pressing each image.
- Rotary presses. Rather than Gutenberg's repurposed wine-press design, type was placed on a drum, with sheets fed through the mechanism.
- Electric drive. Like steam, but less steamy and more sparky.
- Web presses. Rather than individual sheets, a continuous sheet of paper. This is where paper-on-rolls came into being.
- Speaking of which, paper manufacturing was improving, and costs falling, all through this period.
- At the same time literacy rates were increasing from ~10-25% ~1700 to 95%+ by 1900. The people could now read.
- Typesetting enhancements, including oil-based inks, offset-type (where the print impression is a 3rd generation from the type originally used to cast the intermediate slug), linotype, multi-colour presses, improved engraving (for images), and eventually photo-lithography.
By the end of the century a high-speed electrically-powered Linotype web press could achieve a million impressions an hour or more.
Compare with webserver hit rates and their improvement from 1990 - 2020.