If you require payments, you then have credit card companies and Paypal restricting who (i.e. which countries) gets access to it.
Income from donations isn't guaranteed, and thus provides a weak incentive for universities to provide these kinds of courses. I'd also wager that donations would fizzle out as this sort of thing became more commonplace.
US Government grants would provide guaranteed incentives for American universities to offer these kinds of courses, which would educate your populace and bolster the appeal of your higher education institutions to potential overseas students. The latter point would lead to many knock-on economic benefits (e.g. immigrant students deciding to stay in the US).
(oh, but rabble rabble gubment rabble bad rabble rabble because this is HN where libertarian capitalists roam free)
Besides students or government paying, there are several other business models that could be considered, including employers sponsoring in exchange for exposure to the best students.
That said, governments already subsidize education in many countries. We should be demanding that the investment get us a better return!
I really wonder if this is true. I've looked at the text and it seems pretty intro-level. What would the certificate of completion look like on a resume?