I have been using Amazon Smile and Smile Always for MIRI for about a year.

IIRC, Amazon Smile used to be listed on MIRI's Donate for free page, but has since been replaced by "Good Shop". Good Shop appears to give a higher percentage, but I was unable to get the browser extension working so that it happened automatically, so I still use Smile. If anyone knows of a way to get it working, I'd be happy to hear it. But I tried to do it manually for a while, and I just don't remember often enough.