Why does my Shop Gui Duplicate Items when I Click it?

I am trying to make a Shop Gui for a game, and whenever I open and close the gui, it duplicates the item that I'm trying to buy and I get 2 items in my inventory. I am using a remote function.

Local Script:

-- Service Variables
local players = game:GetService("Players")

local serverStorage = game:GetService("ServerStorage")

local replicatedStorage = game:GetService("ReplicatedStorage")

-- Variables
local shopFrame = script.Parent:WaitForChild("ShopFrame")

local itemsFrame = shopFrame:WaitForChild("ItemsFrame")

--Fire Remote Function
script.Parent:WaitForChild("OpenButton").MouseButton1Click:Connect(function()
	if shopFrame.Visible == false then
		replicatedStorage:WaitForChild("ShopFunction"):InvokeServer(script.Parent)
	end
end)

Server Script:

-- Service Variables
local players = game:GetService("Players")

local serverStorage = game:GetService("ServerStorage")

local replicatedStorage = game:GetService("ReplicatedStorage")

local soundService = game:GetService("SoundService")

replicatedStorage:WaitForChild("ShopFunction").OnServerInvoke = function(player, gui)
	-- Variables
	local shopFrame = gui:WaitForChild("ShopFrame")

	local itemsFrame = shopFrame:WaitForChild("ItemsFrame")
	
	-- Make the Shop Visible
	shopFrame.Visible = true
	
	-- Item Bought Button Functions
	itemsFrame:WaitForChild("ItemButton1").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool1"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton1").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton1").Text = "$50 Item1"
		end
	end)
		
	itemsFrame:WaitForChild("ItemButton2").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool2"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton2").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton2").Text = "$50 Item2"
		end
	end)	
		
	itemsFrame:WaitForChild("ItemButton3").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool3"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton3").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton3").Text = "$50 Item3"
		end
	end)	
		
	itemsFrame:WaitForChild("ItemButton4").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool4"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton4").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton4").Text = "$50 Item4"
		end
	end)
		
	itemsFrame:WaitForChild("ItemButton5").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool5"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton5").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton5").Text = "$50 Item5"
		end
	end)
		
	itemsFrame:WaitForChild("ItemButton6").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool6"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton6").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton6").Text = "$50 Item6"
		end
	end)
		
	itemsFrame:WaitForChild("ItemButton7").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool7"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton7").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton7").Text = "$50 Item7"
		end
	end)
		
	itemsFrame:WaitForChild("ItemButton8").MouseButton1Click:Connect(function()
		if player:WaitForChild("leaderstats"):WaitForChild("Money").Value >= 50 then
			player:WaitForChild("leaderstats"):WaitForChild("Money").Value = player:WaitForChild("leaderstats"):WaitForChild("Money").Value - 50
			serverStorage:WaitForChild("Tool8"):Clone().Parent = player:WaitForChild("Backpack")
		else
			itemsFrame:WaitForChild("ItemButton8").Text = "You do not have enough money to buy this item."
			wait(2)
			itemsFrame:WaitForChild("ItemButton8").Text = "$50 Item8"
		end
	end)
		
	-- Close Button Function
	shopFrame:WaitForChild("CloseButton").MouseButton1Click:Connect(function()
		shopFrame.Visible = false
	end)
	return
end