Maybe I'm late to the party on this, but I was made aware of the following in an email from my father about a month ago. I figure it is always a good thing to direct more money to the causes I care about.
If you shop on Amazon, you can set it up so that the donate .5% of your purchases to a charity of your choice. SAF and the NRA are both on that list. The following is from Amazon's website:
AmazonSmile is a website operated by Amazon with the same products, prices, and shopping features as Amazon.com. The difference is that when you shop on AmazonSmile, the AmazonSmile Foundation will donate 0.5% of the purchase price of eligible products to the charitable organization of your choice.
View Quote
Basically, just go to smile.amazon.com and set up your charity. When you are ready to purchase, start at smile.amazon.com and shop away.