Club. Weight 2.
Staff. Two handed. Weight 1.

Bundle of Arrows. 3 Ammo. Weight 1. Cost 1.
Elven Arrows. 4 Ammo. Weight 1. Cost 20.

Knife. Weight 1. Cost 2.
Throwing Knife. Weight 0. Cost 1.

Dungeon World

In the first case, half a staff weighs twice as much as a whole staff. I would blame “game balance”, but Dungeon World doesn’t play game balance. Probably going to swap those weights. Club, Weight 1. Staff, Weight 2.

In the second case, two bundles of Arrows give you 6 Ammo, 2 Weight, costs two coins. Elven Arrows weight less, cost ten times the price, and gives you 2/3 the Ammo. Probably going to increase the price for Bundle of Arrows to 2 coins, increase the Ammo of Elven Arrows to 6, and make Elven Arrows “uncommon”.

In the third case (which we have a former player to thank for pointing out) there is no reason not to buy two throwing knives (so you always have a spare) and just throw them at targets from close to near range.
Probably going to add “Ammo:2” to throwing knives, bump the Weight to 1, and the cost to 5.

May also add a “two Weight 0 things have a Weight of 1” rule, to prevent the infinite healing potion issue.