Can you show me how I would print it locally please?
In the studio ribbon bar there’s a toggle that you can use while testing to go between client and server.
By default it’s on client when you run.
I cant seem to find it. Can you screenshot it perhaps?
I printed it in the command bar, so here you go.
late reply 
silly me, i always forget theres a player argument provided as the first argument
You’re getting this error because you index:
which sets the game’s StarterTools. What you would do instead is either set it in the player’s backpack, or in their character if they have it equipped.
if gold.Value >= 100 then
local Katana = Player.Backpack:FindFirstChild("Katana") or Player.Character:FindFirstChild("Katana") -- Get the katana tool in the player's backpack or if they have it equipped, it will be in the player's character.
Katana.Damage.Value += 100 -- The += operator is more optimized and easier to use.
gold.Value = gold.Value - 100
print("You have boosted your Sword's damage")
else
I hope this helps!
you need to make an event for the button, here is an example:
local button
local event
button.MouseButton1Click:Connect(function()
game.ReplicatedStorage:FindFirstChild(event):FireServer()
end)
then move the old script from the button to the event and edit it so that it works