A book from a machine is a rare but interesting format. It works where people wait.
A book machine usually sells small-format editions that fit spirals or lockers. It works at stations, airports, hospital waiting rooms, and hotels – wherever people have time and there is no bookshop nearby.
Formats and dispensing
Pocket editions fit spirals. Larger books need lockers or a lift so they are not damaged.
Choosing a device
The page with vending machines (publisher's site) describes different dispensing mechanisms.
FAQ
Which books sell best? It depends on the site. The operator picks titles based on sales.
Does it take cards? Usually yes. Check the device's signs.