This ESP32 comes with a battery holder at the back to provide power using a 18650 battery.
Scroll down to find the ESP32 at different stores and find the best price.
Ebay.com
Shrsl.com
Aliexpress.com
£11.90
1 new
from £11.90
as of July 11, 2019 9:35 pm
Amazon.co.uk
$18.09
1 new
from $18.09
as of July 11, 2019 9:35 pm
Amazon.com