In common commercial english, i would read that as “this merchant will offer to trade any of the books for an amoumt of currency equal to half the book’s cover price plus $1.”

Such vagueness also suggests sufficient informality that the merchant may either accept seperate offers or veto the general rule on a case-by-case basis.

The elecrelically semi-literate side, obviously.

I mean, isn’t it a usb_c cable that the manufavtuer claims can handle 10 amps of current at once? (which i think may be on the low side)