I'm on the same boat.
I don't feel comfortable sharing CC details for a free service I might be interested to try (even though I won't have much time until next year to do something), and doesn't seem fair "cheating" the system using a fake one.
Just a suggestion, check the behaviour of the "do_it" div. If I click on it and then click outside without writing anything, the div will collapse leaving a blank area, and it will not be possible (or it will be very hard) to open it again.