Banggood.com
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.
Ebay.com
€2.71
in stock
1 new
from €2.71
as of November 25, 2020 9:03 am
Amazon.es
£6.80
in stock
1 new
from £6.80
as of November 25, 2020 9:03 am
Amazon.co.uk
€9.49
in stock
3 new
from €9.49
as of November 25, 2020 9:03 am
$11.99
in stock
1 new
from $11.99
as of November 25, 2020 9:03 am
Aliexpress.com
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: