Add Coupons during Shopping with 'Coupons at Checkout' Extension

‘Coupons at Checkout‘ extension works the same way as ‘Retailmenot’, only difference is you don’t have to visit an external site to find the coupons for the shopping site, it shows up right where you are shopping like the image below. You can apply the coupons available directly and save money instantly. 

I tested it in Amazon, it works as advertised, just hover over the coupon or gift code area, you will see the list of coupons for the site. Another must-have extension for shopping.