Scroll down the page to compare the WeMos D1 Mini Board price at different stores.
Recommended reading: Best ESP8266 Wi-Fi Development Board
The WeMos D1 Mini offers 4MB flash memory, 11GPIOs, 1 ADC pin in a minimal and small setup. So, if you need something that consumes less power for a more economical project, this is a good option.
Learn more about the ESP8266 board: