Buyer's Guidebook (5e Equipment)
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Wondrous Item, legendary
It looks like either of the below:
A brand new hardcover book with the title "Buyer's Guidebook", by an author named "Helpful Strokov", covered in plastic;
A slightly used book, with the title "Buyer's Guidebook" slightly flattened;
A yellowing book, spine slightly wrinkled and the title fading at the edges;
A yellowed book, spine very wrinkled, the cover page slightly torn, author's name faded;
A very old tattered book, spine missing, cover page missing, and first page slightly torn.
These descriptions indicate the amount of uses the book has left, from brand new, with 5 uses, and torn and tattered with 1 use left. The uses come in the form of ordinary rounded shiny stones with a slightly gold tinge(Stone of the Buyer (5e Equipment)). What for? To go to a place called Plane of the Buyer's Market (5e Environment), where buying anything becomes easy and money disappears fast!