Roblox shop button (remoteevent) script

Server script · Script · ServerScriptService

-- Shop (server side). The server decides if a purchase is allowed.
-- The client only says WHICH item it wants. It never says the price.
-- Needs the Leaderstats (coins) or Save data script so player.leaderstats.Coins exists.

local ITEMS = {
	-- [item name] = { price = coins, tool = name of a Tool in ServerStorage }
	Sword = { price = 50, tool = "Sword" },
	Torch = { price = 20, tool = "Torch" },
}
local BUY_COOLDOWN = 0.5   -- seconds between purchases for one player

local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local ServerStorage = game:GetService("ServerStorage")

-- Make the RemoteEvent if it is not there yet.
local buyEvent = ReplicatedStorage:FindFirstChild("BuyItem")
if not buyEvent then
	buyEvent = Instance.new("RemoteEvent")
	buyEvent.Name = "BuyItem"
	buyEvent.Parent = ReplicatedStorage
end

local lastBuy = {}

buyEvent.OnServerEvent:Connect(function(player, itemName)
	-- 1. Check what the client sent. Never trust it.
	if type(itemName) ~= "string" then
		return
	end
	local item = ITEMS[itemName]
	if not item then
		return
	end

	-- 2. Slow down spam.
	local now = os.clock()
	if lastBuy[player] and now - lastBuy[player] < BUY_COOLDOWN then
		return
	end
	lastBuy[player] = now

	-- 3. Check the player can pay.
	local leaderstats = player:FindFirstChild("leaderstats")
	local coins = leaderstats and leaderstats:FindFirstChild("Coins")
	if not coins or coins.Value < item.price then
		return
	end

	-- 4. Check the tool exists and the player has a Backpack.
	local template = ServerStorage:FindFirstChild(item.tool)
	local backpack = player:FindFirstChildOfClass("Backpack")
	if not template or not backpack then
		return
	end

	-- 5. Take the coins, give the item.
	coins.Value -= item.price
	template:Clone().Parent = backpack
end)

Players.PlayerRemoving:Connect(function(player)
	lastBuy[player] = nil
end)

Button script · LocalScript · Inside the TextButton (StarterGui > ScreenGui > TextButton)

-- Shop button (client side). Sends the item name to the server when clicked.

local ITEM_NAME = "Sword"   -- must match a name in the ITEMS table on the server

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local button = script.Parent
local buyEvent = ReplicatedStorage:WaitForChild("BuyItem")

button.Activated:Connect(function()
	buyEvent:FireServer(ITEM_NAME)
end)