The Best Amazon Feature That Not Enough Shoppers Know About

Daniel Goodman / Business InsiderA scene from the charity:water offices

If you're not already using AmazonSmile when you shop, you should start right now. 

Smile gives Amazon shoppers a way to donate a small percentage of their purchases to almost any charity they want. Once you sign up at smile.amazon.com and choose a charity, 0.5% of your eligible purchases will be donated.

There are nearly one million charities available to choose from, with more getting added every day, and hundreds of thousands of products qualify (you'll see an "Eligible for AmazonSmile donation" badge near the "Add to shopping cart"). 

The service doesn't cost anything to the charities that sign up or the shopper (for that reason, donations are not tax deductible). All you have to do is start your shopping at smile.amazon.com. 

I decided to donate to charity:water, a non-profit organization that brings clean drinking water to people in developing countries. Even though .5% isn't a lot on each purchase, everyone should sign up for Smile because giving something is always better than nothing:

In its annual tally of our insane holiday shopping, Amazon reported that 16 times more Amazon customers shopped on smile.amazon.com than last year, and the company has donated millions of dollars since it launched the program in October 2013. 

Disclosure: Jeff Bezos is an investor in Business Insider through his personal investment company Bezos Expeditions.