How to fix this script so that the player can only buy it once?

Annyeong!Hello!

So I have a shop gui,then there is a buy button,what i want it to do is that i want the player to buy a tool,then the player will not be able to buy it again.It will cost the in game currency,so i do not want it to be in a games form.However it doesn't work.I don't know what is wrong but i tried :FindFirstChild and still did not work

There was also NO output error

Local Script:

local plr = game.Players.LocalPlayer
local Cloud = game.ReplicatedStorage["Flying Cloud"]
local button = script.Parent


button.MouseButton1Click:Connect(function()
	if plr.leaderstats.Scikoins.Value == 100 or plr.leaderstats.Scikoins.Value >= 100 then
plr.leaderstats.Scikoins.Value = plr.leaderstats.Scikoins.Value - 100		
Cloud:Clone().Parent = plr.Backpack
		wait(2)
		warn(plr.Name.."has bought a cloud")
	    else
		warn(plr.Name.."has not enough scikoins")
		if plr.Backpack:FindFirstChild("Flying Cloud") then
			warn(plr.Name.."already has a cloud")
		end
	end
end)

local plr = game.Players.LocalPlayer
local Cloud = game.ReplicatedStorage["Flying Cloud"]
local button = script.Parent


button.MouseButton1Click:Connect(function()

   if plr.Backpack:FindFirstChild("Flying Cloud") then
            warn(plr.Name.."already has a cloud")
		return -- returns the function
        end

    if plr.leaderstats.Scikoins.Value == 100 or plr.leaderstats.Scikoins.Value >= 100 then
plr.leaderstats.Scikoins.Value = plr.leaderstats.Scikoins.Value - 100       
Cloud:Clone().Parent = plr.Backpack
        wait(2)
        warn(plr.Name.."has bought a cloud")
        else
        warn(plr.Name.."has not enough scikoins")
       -- if plr.Backpack:FindFirstChild("Flying Cloud") then -- switch this so it is above the buy system and the script reads it first before subtracting money from the player
          --  warn(plr.Name.."already has a cloud")
       -- end
    end
end)