The least cost software/real time data I have found is QT with Money.net-Software is free (if you don't mind one small ad line) and Money.net for QT is $15/mo. I use it for basic alarming...which works great. Their charts are OK, but it is not capable of taking your strategy formulae and generating buy/sell signals.
They were the only outfit that could also support all the regular NYSE stocks I trade as well as allow price alerts on some of the less traveled Preferreds that I park money in for income. (Schwab's website wouldn't allow Preferred alerts...not that they would do anygood anyhow since their alerts drive off delayed data-(Website....not Streetsmart).
Bruce