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.
Aliexpress.com
Ebay.com
Shrsl.com
£11.90
1 new
from £11.90
as of September 19, 2019 9:50 am
Amazon.co.uk
$17.19
1 new
from $17.19
as of September 19, 2019 9:50 am
Amazon.com