In most cases, that charge isn't passed on to the buyer/donor. When it is, it should be made explicit. Nonprofits sometimes make it an option, e.g. "Add 3% to

In most cases, that charge isn't passed on to the buyer/donor. When it is, it should be made explicit. Nonprofits sometimes make it an option, e.g. "Add 3% to your donation to help offset credit card processing fees".