One of my favorite plug-ins is Honey, a service which will automatically scour the web for discount codes and offer to apply them when shopping online. I've used Honey to get discounts on Amazon, Godaddy, and several other sites.
Honey recognizes the retailer you are at and offers to apply discount codes for free. Even better, when there are multiple codes available Honey will try all of them to see which ones still work, and what will generate the largest discount for you.
You can get Honey at the Chrome web store by simply typing Honey in the search box. While there is an option to register you don't have to register the plug-in. (I haven't yet, more due to forgetting than anything else.)
Unlike a lot of apps that historically promised savings in some form or another Honey doesn't install any sort of spyware on your system. Honey just delivers up savings without any of the badness that apps like BargainBuddy used to bring to the table.
When registering a domain with Godaddy, Honey automatically applied a code that reduced my cost to $0.99 for a year. Sure I could have sought out the code on my own but that would have taken some time. Instead of googling for valid codes Honey just popped up and asked if it could apply codes. After I agreed the price instantly dropped.
It wasn't a huge discount in terms of dollars saved, but as a percentage reduced it was massive. More importantly I was in a rush and probably wouldn't have bothered looking for a code but it automatically came up and put over $10 back in my pocket.
The extension is free, doesn't require registration, and then just helps you out automatically when you need it, so you really have to ask yourself why not use it?
More posts with other helpful plug-ins will be posted, but in the interim I'd suggest adding Honey to your copy of Chrome and start saving.
-The Home Geek