STM32 STM8 ARM Development Board Arduino Programmer debugger

10 euro STM8S103F3P6 system board STM8S STM8 development board minimum core board

5 euro ST-Link V2 stlink mini STM8STM32 STLINK

10 euro STM32F103C8T6 ARM STM32 Minimum System Development Board Module For Arduino
Model: STM32F103C8T6. Core: ARM 32 Cortex-M3 CPU.

10 euro stm32f103c8t6 STM32 Smart V2.0 For Arduino
http://wiki.stm32duino.com/index.php?title=STM32_Smart_V2.0

20 euro STM32VLDISCOVERY STM32F100RBT6B microcontroller, 128 KB Flash memory, 8 KB RAM in 64-pin LQFP
On-board ST-LINK with selection mode switch to use the kit as a stand-alone ST-LINK (with SWD connector)

20 euro Tiva ARM® Cortex®-M4F Based MCU TM4C123G LaunchPad™ Evaluation Kit
ARM Cortex-M4F Based MCU TM4C123G LaunchPad Evaluation Kit (EK-TM4C123GXL) offers these features:

10euro J-Link JLink V8 USB ARM JTAG Emulator Debugger J-Link V8 Emulator J-Link JLink V8 + Adapter Board

Custom development boards are available on request.