The Ball-steel,1/4 is the lowest priced item on this Kickstarter Mechanism schematic.
Some items from this specific schematic: Bolt,socket,8x25, Screw-set-socket,8x8, Ratchet, Screw,6x30.
With a quantity of two pieces, the Circlip-type-c,18mm is the most used part in the KICKSTARTER MECHANISM diagram.