Honey is a Chrome extension that makes it much easier to find coupons and promo codes and Mozilla also has a version of it as an Add-on. The extension/add-on works thusly: It adds a button to your checkout page. You click this button and the extension searches for and applies the coupon codes to your order. You can take a look at some reviews of the add-on here: Log In Can be great especially if you don't have the time to search for coupons and promo codes.
Great idea @Denis Hard and I will consider installing it. I will still look for coupon codes, but many either have expired or have small print and exclusions. Finding a code can be work in itself, so if this works, it is worth it. I wonder if any are sponsored or if it will choose the best code possible at the time?
The add-on/extension looks for coupons all over the net and applies the best one to your order. If you haven't used it yet you could try it and see how much money you could save if you were using the add-on to find coupons. But you can only find coupons for only about 100 stores. You can find the full list of supported stores here: Log In