" Compensation, is my time free?"

No more or less so than a photographer's time is free.

If you do not feel you will get anything out of a shoot you value, then don't do it. 

Getting something you value isn't just money.  Images, experience and networking all have potential value.

Ones time is the most precious commodity there can ever be. It is finite and when it has passed it can NEVER be recovered or replaced. Each of us must decide what our time is worth. Much of the photography here is created using the barter system, TFP, TFCD, TF?? If the pictures from a certain photographer would not be worth your time doing the shoot ask for payment but always remember, the pendulum swings both ways.