A bunch of small coins.
The item id for Buckies in unturned is 6694. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Size_X: 1
Size_Y: 1
Size_Z: 0.1
Amount: 1
Count_Min: 1
Count_Max: 1
Calibers: 1
Caliber_0: 6692
Damage: 0.8
Pellets: 3
Tracer: 48
Blueprints: 2
Blueprint_0_Type: Tool
Blueprint_0_Supplies: 1
Blueprint_0_Supply_0_ID: 1056
Blueprint_0_Supply_0_Amount: 3
Blueprint_0_Products: 1
Blueprint_0_Build: 27
Blueprint_0_Map: Easter
Blueprint_1_Type: Tool
Blueprint_1_Supplies: 1
Blueprint_1_Supply_0_ID: 1057
Blueprint_1_Supply_0_Amount: 3
Blueprint_1_Products: 1
Blueprint_1_Build: 27
Blueprint_1_Map: Easter