woothemes/woocommerce — pull request #6822 by helgatheviking (2014-11-22 00:06:50+00:00)
Title: always save a 0 price if none entered #6739

Originally, I had a message in there, but then I remembered that user's with Name Your Price enabled won't even see the regular price input, so a message about a zero price would be very confusing.