Sad to say there are people out there that are dishonest. Willing to take advantage and hold on to their money and make you work for free (spec work) or super cheap. Tell em' "NO WAY!" A good way of looking at it, is pretend your a plumber. This client calls in with a clogged toilet, and he tells the plumber to do this for free and he will get credit and have a great portfolio. He will tell the client to "go to hell." simple..
All these years we put in our craft. Don't be a victim, I ran into this great podcast. check it out. And know where you stand. Man vs. Art