MetaTrader4 (commonly called MT4) is free chart software developed by MetaQuotes Software Corp.
This software is sophisticated, light, and runs crisply.
You can develop your own indicator in a programming language called MQL (MetaQuotes Language). Programmers all over the world develop various indicators and disclose them free.
Incidentally, Movable Type4 (also commonly called MT4) is also free software but blog software.
-->Go to How to Download MetaTrader4
-->Go to How to Display Indicators