Debug interface: The STM8S family uses a simple single wire serial debug interface called SWIM and consumes only one extra pin for the SWIM connection other that the VDD, GND and RESET.
Cost & Ordering: The STM8S-DISCOVERY board costs only around Rs 700/- and can be a very handy tool for prototyping. In India you can order this tool from Kits-n-Spares /element14 website .
Prototyping: The STM8S family microcontrollers come with a wide range of package choices in which i prefer to use the 32pin LQFP package which is easier for etching and soldering on prototype boards.
Development environment: The STM8S is supported by ST microelectronics own development tool suite called ST-DEVELOP and other third parties like IAR. I prefer to use IAR emebedded work bench STM8S-kick start edition which is free and provides a neat developing & debugging platform with Live watch and unlimited breakpoints features.