Aliexpress have begun shipping a low cost breakout/development board for the STM32F030. The board can be programmed using ISP and a USB/UART interface as shown below. The boards cost varies but I got mine for 1.58 Euro.
I had previously worked on some suitable examples which can be found over here.
These examples are built using a Makefile however I have found that the following script is a lot easier to work with (just make sure your PATH environment variable includes the directory where the arm compiler programs and utilities are stored).
arm-none-eabi-gcc -static -mthumb -g -mcpu=cortex-m0 *.c -T linker_script.ld -o main.elf -nostartfiles arm-none-eabi-objcopy -g -O binary main.elf main.bin arm-none-eabi-objcopy -g -O ihex main.elf main.hex
You then program the chip by linking the Boot0 pin and 3v3 with the jumper, hit reset and enter the following:
stm32flash -w main.hex /dev/ttyUSB0
To run your program, move the jumper so that it links Boot0 to GND and hit reset.
The USB/UART interface appeared as /dev/ttyUSB0 on my system, yours may vary (on Windows it will be something like COM3)
stm32flash can be downloaded from a number of sources. On Ubuntu it can be installed with
sudo apt-get install stm32flash
The ARM cross compiler suite can be downloaded from launchpad.net