I personally have a dramatic distaste of advertisement in any shape or form
I mostly agree, though maybe not quite so strongly. I would continue to donate for the extra goodies, even if they were available via opt-in advertising. It totally ruins the immersion for me. But if other people are willing to accept them as "the price of doing business", then I don't mind them opting to look at them.
As another possibility, have you considered getting an affiliate account with Amazon? I know quite a few web sites that let you buy stuff through their affiliate link. It doesn't cost the the buyer anything, but gets you a percent or two kickback from Amazon. You could just post the affiliate link somewhere, like the Donation page. It doesn't need to be in-your-face, or on every page.
