Banggood - 1pcs LM2577 DC to DC Buck Converter Power Supply Step Down Module
$3.09
Banggood.com
Scroll down the page to compare the step down buck converter price at different stores.
A step-down buck converter is a DC-to-DC power converter which steps down voltage from its input to its output.
Aliexpress- 1 pcs LM2596 DC to DC Buck Converter Power Supply Step Down Module
Aliexpress
Amazon.es - 1pcs LM2596 DC to DC Buck Converter 3.0-40V to 1.5-35V Power Supply Step Down Module
Amazon.es
eBay - 1pcs LM2596 DC to DC Buck Converter Power Supply Step Down Module
$1.01
eBay
Banggood - 1pcs LM2577 DC to DC Buck Converter Power Supply Step Down Module
$3.09
Banggood.com
Amazon.com - 6pcs LM2596 DC to DC Buck Converter 3.0-40V to 1.5-35V Power Supply Step Down Module
$10.99
Amazon.com
Amazon.co.uk - 6pcs LM2596 DC to DC Buck Converter 3.0-40V to 1.5-35V Power Supply Step Down Module
£11.14
Amazon.co.uk