Is this only for Prime members? If so, that sounds a bit self-serving for Amazon. "We will donate to your charity, but only if you pay us to become an Amazon Prime member first." That just sounds wrong.
I'll look into this. I have a Wish List on Amazon that I'd gladly turn into purchases to support ETS. But not if Amazon requires me to become a Prime member to do that. That would really leave a bad taste in my mouth.