OptionGuru giving some terrible advice here.
Live feed for stocks is not free - you only get BATS real-time for free but they are only a small part of the market, for correct quotes you pay $1.50 for NASDAQ, NYSE and AMEX each. US futures are anything from $2.50 to $125 per month.
And no, you don't need to subscribe to anything at all, trading permissions are not connected to real-time quotes.
Do you need to subscribe to those quotes to trade? I don't think so.
When I had my IB account a few years ago I setup a watch-list of stocks, options and futures (YM, GC and the Singapore Mini Nikkei 225 Index ) using the browser based platform. The watch-list had real-time quotes and I could buy or sell with a few clicks. I wasn't subscribed to anything.
