Does someone have a script money on kill on npc that adds the cash to a gui not leaderboard ?

This is how I would do it. So first i made a tool to attack the npc, just a part for the handle this is the script inside the tool

local debounce=false

script.Parent.Handle.Touched:Connect(function(hit)
if hit.Parent:FindFirstChild("Humanoid")~=nil then
local human=hit.Parent:FindFirstChild("Humanoid")
if debounce==false then
debounce=true
hit.Parent:FindFirstChild("attacker").Value=game.Players:GetPlayerFromCharacter(script.Parent.Parent)
human:TakeDamage(10)
wait(1)
debounce=false
end
end
end)

this damages the npc and sets the attacker value inside to the player, this is important, i put an object value inside the npc called attacker, so when the npc dies it will give cash to the attacker. now cash is inside leaderstats, inside a folder in leaderstats called Stats, reason being we dont want to show the cash on a leaderboard, since you said you want it as a gui. Next is the script inside the npc model.

local debounce=false
script.Parent.Humanoid.Died:Connect(function()
if debounce==false then
debounce=true
local player=script.Parent.attacker.Value
if player~=nil then
player.leaderstats.Stats.Cash.Value=player.leaderstats.Stats.Cash.Value+math.random(25,35)
end
script.Parent:Destroy()
end

end)

so the player gets cash when they kill the npc with the tool. Then we need to add the leaderstats to the player, with this script in serverscript service:

game.Players.PlayerAdded:Connect(function(player)
local leaderstats=Instance.new("Folder")
local Stats=Instance.new("Folder")
local Cash=Instance.new("IntValue")
leaderstats.Name="leaderstats"
Stats.Name="Stats"
Cash.Name="Cash"
Cash.Parent=Stats
leaderstats.Parent=player
Stats.Parent=leaderstats
end)

then because you want it in a gui, we make the gui and textlabel to display the cash value, since adding numbers to the text property of gui would be wierd.

while wait() do
local leaderstats=game.Players.LocalPlayer:WaitForChild("leaderstats",60)
script.Parent.Text="$".. tostring(leaderstats.Stats.Cash.Value)
end