Tool:Clone().Parent = plr.StarterGear and parent to inventory folder Not Working?

So I have a similar game, where I have tool gamepasses.

The problem your making is this:

Compare your code with mine.

local plr = game.Players.LocalPlayer
02  local Players = game:GetService("Players")
03  local ReplicatedStorage = game:GetService("ReplicatedStorage")--gets ReplicatedStorage
04  local ToolsFolder = ReplicatedStorage:FindFirstChild("Tools")-- gets the tools folder
05  local InventoriesFolder = ReplicatedStorage:FindFirstChild("Inventories")-- gets the inventories folder
06  local button = script.Parent-- gets the button
07  local SpeedCoil = ToolsFolder:FindFirstChild("SpeedCoil")
08  print("VariablesDone!")--prints "VariablesDone!"
09  --MainScript--
10  button.MouseButton1Click:Connect(function()--when a player presses the button in left click
11      print("Pressed")-- when a player presses the button then it will print out "Pressed"
12      local inventory_folder = InventoriesFolder[plr.Name]
13      print("No Errror BRUH")
14      SpeedCoil:Clone().Parent = plr.Backpack
15      SpeedCoil:Clone().Parent = plr.StarterGear
16      SpeedCoil:Clone().Parent = inventory_folder
17      end)

Now check Mine:

local id = 10409444 
game:GetService("MarketplaceService").PromptGamePassPurchaseFinished:Connect(function(plr,ido,purchased)
    if purchased and ido == id then 
        game.ServerStorage.Tools.DiamondSword:clone().Parent = plr.Backpack     
    end
end)
game.Players.PlayerAdded:Connect(function(plr)
    plr.CharacterAdded:connect(function(char)
        if game:GetService("MarketplaceService"):UserOwnsGamePassAsync(game.Players[char.Name].UserId, id) then
            game.ServerStorage.Tools.DiamondSword:clone().Parent = plr.Backpack     
        end
    end)
end)

Moderate this in your own way.

I don't have much experience with the StarterGear folder, but I assume that the server is cloning this folder to your backpack whenever a player spawns. As a result, attempting to put tools in StarterGear from the client may not work. You'd have to use a RemoteEvent.

local plr = game.Players.LocalPlayer
local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")--gets ReplicatedStorage
local ToolsFolder = ReplicatedStorage:FindFirstChild("Tools")-- gets the tools folder
local InventoriesFolder = ReplicatedStorage:FindFirstChild("Inventories")-- gets the inventories folder
local button = script.Parent-- gets the button
local Tool = ToolsFolder:FindFirstChild("SpeedCoil")
local GiveToolRemote = ReplicatedStorage:WaitForChild("Tools"):WaitForChild("RemoteEvent")
print("VariablesDone!")--prints "VariablesDone!"
--MainScript--
button.MouseButton1Click:Connect(function()--when a player presses the button in left click
    print("Pressed")-- when a player presses the button then it will print out "Pressed"
    local inventory_folder = InventoriesFolder[plr.Name]
    print("No Errror BRUH")
    GiveToolRemote:FireServer(Tool.Name)
end)


--PUT THIS IN A SERVER SCRIPT IN SERVERSCRIPTSERVICE
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Tools = Instance.new("RemoteEvent", ReplicatedStorage.Tools)
local ToolsFolder = ReplicatedStorage:FindFirstChild("Tools")
local InventoriesFolder = ReplicatedStorage:FindFirstChild("Inventories")

Tools.OnServerEvent:Connect(function(player, Toolname)
    local Tool = ReplicatedStorage:FindFirstChild(Toolname)

    if Tool then
        Tool:Clone().Parent = player.StarterGear
        Tool:Clone().Parent = player.Backpack

        local inventory_folder = InventoriesFolder[player.Name]
        Tool:Clone().Parent = inventory_folder
    end
end)