Recommended reading: Best ESP8266 Wi-Fi Development Board
Scroll down the page to compare the ESP-01 Board price at different stores. You might also consider buying a ESP-01 Serial Programmer Adapter.
ESP8266 is a highly integrated chip designed for the needs of a new connected world. It offers a complete and self-contained Wi-Fi networking solution, allowing it to either host the application or to establish an Internet connection.
Learn more about the ESP8266 board: