The more you buy from one seller, the further your postage goes
Postage is often priced by weight, not by how many books you’re buying. So add more books from the same seller and the postage cost may stay the same or only go up by a little, making buying 2 or 3 books much better value than buying just 1 book.
Your basket shows you the postage as you add books, so you can watch it in real time, no surprises, just an easy way to get more books for less.