If you have dormant sub accounts (no money in them) then just unsubscribe data for them. If you run out money in an active account (not even $10 spare) such that you cant get real time data then you can still close positions at market and use free 20 minute delayed data if needed. Real time data is completely optional at IB. You can still submit orders without it.
You can get free futures data with a TDAmeritrade account and trade without data at IB. Not that I would recommend that, not having the software integrated with the data (and TWS tends to be annoying when you try to trade without data) can be a cost on it self
It's optional for most order cases but not functional for some items -- like rolling over options, you need to know the real time quotes for two items, their spreads, etc; the IB roll over screen for doing that rather involved order item can quickly do it, but is non functional with out quotes.