Empty, flat folded storage bags which may be valve bags are prepared for filling with a flowable material, by seating and stacking a plurality of the bags on a fixed elevation base within a chamber of a bag holding magazine assembly, the resulting stack defining an initial stack rising from a lowermost one the bags on the base to an uppermost one of the bags. In a first cycle of operation, all but the lowermost bag is raised away from the base, the raised bags defining a depleted stack of bags. Then, while the depleted stack remains raised, the lowermost bag is removed from the chamber through a chamber outlet opening. Then, the depleted stack is lowered to seat a new lowermost bag on the base to complete first cycle. The cycle is repeated for each lowermost bag. When each bag is removed from the magazine chamber the bag may be conveyed to a bag pick-up position located away from the magazine assembly and, from there, automatically picked with a carrying tool located at the end of a robotic arm and transported to a bag filling station for filling with the flowable material. In the case of valve bags, the valve may be opened by the carrying tool at the time of pick-up.