What free IDE does everyone use for the stm32?
Definitely mbed.org
Mbed is a free ARM-supported online IDE with open libraries, revision control &amp; online community.
The IDE runs in your web browser, so you can work from any PC and collaborate with people around the world.
The STM32L152RE (Cortex M3, 512k Flash/80k RAM) is supported with the $10 Nucleo-L152 board.

I had my first STM32L1 up and running "Mbed Blinky" (a simple LED flasher) in 10 minutes.