local id = Coloque o numero aqui!!

game:GetService("MarketplaceService").PromptGamePassPurchaseFinished:Connect(function(plr,ido,purchased)
    if purchased and ido == id then
        plr.Character.Humanoid.WalkSpeed = 30
    end
end)

game.Players.PlayerAdded:Connect(function(plr)
    plr.CharacterAdded:connect(function(char)
        if game:GetService("MarketplaceService"):UserOwnsGamePassAsync(game.Players[char.Name].UserId, id) then
            char.Humanoid.WalkSpeed = 30
        end
    end)
end)