Back in 2024, Espressif Systems introduced the ESP32-C61 2.4 GHz WiFi 6 and Bluetooth LE (BLE) SoC as a low-cost variant of the ESP32-C6 without an 802.15.4 radio, a single RISC-V core, and lower-capacity SRAM (320KB vs 512KB). Besides the ESP32-C61-MINI-1/1U module, you can also use the ESP32-C61-DevKitC-1-N8R2 development board to get started, sold for $9 on AliExpress, or $12 on Amazon. Besides the ESP-IDF framework and Arduino, I can also see an alpha version of the CircuitPython firmware for the board. The ESP32-S31-WROOM-3 module is sold for $4.95 with 16 MB of flash and 16MB of PSRAM, and the ESP32-S31NRV16 SoC for $3.76. We also use affiliate links in articles to earn commissions if you make a purchase after clicking on those links.