Citizens of Poland had to exchange foreign currency they had into these notes (bony in Polish plural), issued by the government-controlled Bank Pekao.
All Polish citizens, who received money orders from the so-called “second payments area” (pl:drugi obszar płatniczy), which covered Western Europe and North America, were not paid in real cash - dollars, pounds or marks, but instead, were issued with bons.
This applied to those who received all kinds of payments from the West - salaries, pensions, monetary gifts, grants, donations.
These stores sold imported luxury products, otherwise not available on the domestic market - candy, coffee, chocolate, liquors, household appliances, cars.
Following the collapse of the Communist system, foreign currency trade became legal, which meant that the bons lost its raison d'être.