Cheapest microcontroller. The STM32 microcontroller series, developed by STMicroelectronics, is a highly popular and widely used family of microcontrollers in the embedded systems industry. Renowned for their versatility, performance, and extensive range of features, STM32 microcontrollers have become the go-to choice for a diverse range of applications, including consumer electronics, industrial automation, Internet of Things (IoT) devices, and more.