ESP-01S-I — Ai-Thinker
ESP8266 WiFi module, 8MB flash, PCB antenna, industrial range -40..+85C

Category: Module

Pricing
  LCSC         $0.83
  Mouser       $1.01
  DigiKey      $1.06
  Farnell      $1.21

Manufacturer: https://www.ai-thinker.com