How can I try Craft Pro?
Douglas's answer is correct... Also, if you'd simply like to try Craft Pro before purchasing it, you can do so while running Craft in your local environment.


  https://craftcms.com/support/try-craft-client-pro


UPDATE:

It's now possible to try Craft Pro from any non-public domain:


  https://pixelandtonic.com/blog/test-craft-client-pro-from-any-non-public-domain