How do I make someone visible with a developer product?

I am currently working on an obby where the player is invisible. But I have 1 problem. I want to make a developer product that you can buy so you turn visible for 10 seconds. I've watched a lot of tutorials and forum posts but none of those seem to work. Can anyone help me out?

I have no idea if this works cuz I'm broke

local developerProductsPage = game:GetService("MarketplaceService"):GetDeveloperProductsAsync():GetCurrentPage()
local DeveloperProducts = getmetatable(newproxy(true))
for _, developerProduct in pairs(developerProductsPage) do
	table.insert(DeveloperProducts,developerProduct.DeveloperProductId)
end
local function GetDescendantTableClass(Object,Class)
	local tab = getmetatable(newproxy(true))
	for _,v in next,Object:GetDescendants() do
		if v:IsA(Class) then
			table.insert(tab,v)
		end
	end
	return tab
end
game.Players.PlayerAdded:Connect(function(Player)
	if Player then
		game:GetService("MarketplaceService").PromptPurchaseFinished:Connect(function(P,ID,PURCHASED)
			if P == Player and DeveloperProducts[ID] and PURCHASED == true then
				for _,part in next,GetDescendantTableClass(Player.Character,"BasePart") do
					if part.Name ~= "HumanoidRootPart" then
					part.Transparency = 1
					end
				end
				wait(10)
				for _,part in next,GetDescendantTableClass(Player.Character,"BasePart") do
					if part.Name ~= "HumanoidRootPart" then
						part.Transparency = 0
					end
				end
			end
		end)
		
	end
end)

I think that MarketplaceService is the best option for this. Here is a block of code how to do that:

local MarketplaceService = game:GetService("MarketplaceService")

game.Players.PlayerAdded:Connect(function(player)
if MarketplaceService:PlayerOwnsAsset(--your id--) then
-- what you want to do if the player has your gamepass -- 
end
end)

Also, a person commented that it was wrong, so I'm revamping it: Its Probably MarketplaceService, but I don't use gamepassservice so just watch a tutorial because idk