If you are a purchaser or "buyer" for a pink elephant factory, you arrange to buy all the pink dye, the elephant molds, and the packaging. You also might just be a "consumer," buying milk at the store.
Purchasers at large companies may oversee millions or even billions of dollars in deals a year. They are responsible for buying the products — or the stuff needed to make the products — that are to be resold. Another type of purchaser is responsible for maintaining inventories of office supplies or furniture for an office building.