How do I convert a string to an integer? [solved]

I wrote a pay command, and it seems to work fine, except for this error

11:02:48.400 - ServerScriptService.PayCommand:10: attempt to compare string with number

How do I turn the string to an integer?

--Gitrog's Pay Command
--Retrieves a money tool from the specified location, and when that tool is used it gives that much money.
--Script requires a money leaderstat

local location = game.ServerStorage.SpawnerStorage --Where you are storing MoneyTool

function onChatted(message, player)
    if message:sub(1,5) == "/pay " then
        local money = message:sub(6)
        if player.leaderstats.Money.Value >= money then
            location.MoneyTool:Clone().Parent = game.Players[player.Name].Backpack
            local moneyTool = game.Players[player.Name].Backpack.MoneyTool

            moneyTool.Value.Value = money
            player.leaderstats.Money.Value = player.leaderstats.Money.Value - money
        else
            print(player.Name .. " does not have $" .. money)
        end
    end
end

game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(message) onChatted(message, player) end)
end)