Quantity   Component name
1 × ST-Link V2 ICP adapter (e.g. $2.00 from AliExpress) The ST-Link on an STM8S Discovery Board can be used, too
1 × serial interface adapter /w 3.3V signal level (e.g. $0.60) e.g a USB interfacea with a CH340, or better a PL2303, chip
1 × STM8S target device as listed in the GitHub Wiki (e.g. a $0.70 "STM8S103F3P6 minimal system board") e.g. "STM8S103F3P6 STM8S development board" from your favorite China source
1 × Some headers, patchwires, breadboard etc (about $2.00) and other things you fancy, e.g. a RC-servo, SPI display, LEDs ...