From Guild Wars 2 Wiki
Equip a slingshot.
— In-game description [?]
The slingshot can be purchased from the last shop World 1 - Zone 3, for 225 baubles.
- Character shoots in the direction he or she is facing, not towards targeted foe.
- Each shot costs 1 .
- The use of baubles as ammunition may be a reference to a bow in one of the early Zelda games, where ammunition was tracked through each arrow you fire costing a rupee.