Two Ikea Ivar floor-to-ceiling shelving units, 70.5” T, 19.5” deep, 35”W (great for storage) = 4 side supports + 8 shelf boards + 2 cross-braces (can combine to three units, 103” wide) – near-new $80 (less than;1/3 of Ikea price) obo. Picture shows one unit.

ALSO: Same type of Ivar shelves as above with 35"W but 12” deep, somewhat aged. Several side units / heights: 48.5”, 70.5”, 89”; two dozen shelf boards. Assembled 35” wide or combine to c.69" wide, 103" wide, etc.. – Price: minimal as long as you take plenty of side units and shelf boards.