--Server Script:

local ms = game:GetService("MarketplaceService")
local gamePassRF = game:GetService("ReplicatedStorage"):WaitForChild("GamePassRF")
local vipBoughtRE = game:GetService("ReplicatedStorage"):WaitForChild("VipBoughtRE")

function purchaseDone(player, id, success)
    if success and id == 4604785 then
        vipBoughtRE:FireClient(player)
    end
end

function hasPass(player, id)
    return ms:UserOwnsGamePassAsync(player.UserId, id)
end

gamePassRF.OnServerInvoke = hasPass
ms.PromptGamePassPurchaseFinished:Connect(purchaseDone)

--Local Script:
local player = game.Players.LocalPlayer
local button = script.Parent.Frame:WaitForChild("TextButton")
local gamePassRF = game:GetService("ReplicatedStorage"):WaitForChild("GamePassRF")
local vipBoughtRE = game:GetService("ReplicatedStorage"):WaitForChild("VipBoughtRE")
local isSped = false

local id = 4604785

local playerHasVIP = gamePassRF:InvokeServer(id)

function toggleSpeed()
    if player.Character and playerHasVIP then
        if isSped then
            button.Text = "Speed up"
            player.Character.Humanoid.WalkSpeed = 16
            isSped = false
        else
            button.Text = "Slow down"
            player.Character.Humanoid.WalkSpeed = 30
            isSped = true
        end
    else
        if not playerHasVIP then
            game:GetService("MarketplaceService"):PromptGamePassPurchase(player, id)
        end
    end
end

function purchased()
    playerHasVIP = true
end

vipBoughtRE.OnClientEvent:Connect(purchased)
button.MouseButton1Click:Connect(toggleSpeed)