https://ru.wikipedia.org/wiki/%D0%A2%D0%BE%D0%B2%D0%B0%D1%80...
>In the USSR, retail stores weren't allowed to promptly raise prices on popular items or lower prices on unpopular ones. One way to circumvent this was through "loading": stores would combine a popular (scarce) item with one or more unpopular ones into "food sets" on their order desks, preventing customers from purchasing the scarce item separately.