Barter between individuals and firms. People and firms would hoard up whatever goods they could and trade it for other goods, services or social connections that would give them the desired goods or services. One expression of that trend was the cultural icon of the "procurement officer" - basically a traveling salesman responsible for finding and procuring goods (raw material, spare parts, machinery, etc.) for his firm. Although the position had no raison d'etre under a centrally planned system (resources were supposed to be allocated based on the planned objectives and existing capacity) - every firm employed an army of such officers to barter for the resources it needed.
Wojtek