This is interesting, and I'll try to re-rail this thing a bit in my response. This is just me, your attitude differs and the OP's attitude may also differ. I'm just pointing out that there are people in the world who view these things differently.
There's no way I would do a $0 contract. If you're going to make me mess with paper, you're paying me. Implicit in your, and possibly tyler's, responses is that you take for granted the desire to control the destiny of your work. I don't. If I gave someone a digital file, it would be without restrictions. Do what you will. Why would I do this? Because restricting things requires effort on my part which I seek to avoid, and which brings me no benefit that I can understand.
- If your emotional attachment to your work is such that you don't want people to do just anything with it, well, that's fine. I have no problem with that, I understand it. I don't have such an attachment.
- If your controlling and selling your intellectual property is a business, then that too is fine. You need to control it to make money. Great! That's also not me.
I am an amateur. I occasionally make something I like. By giving you a copy of what I have made, I do not in any way I can see enable you to harm me. If you go and make a great deal of money with my image, well, good for you. If you tonemap my image into a horror-show and cover america with billboards, well, we probably won't be friends any more but it hasn't actually hurt me. I make intellectual property for a living, and have for 20-odd years now. It has paid me well. I have spent far more time than I should have thinking about IP and "what it all means" and part of the result is that I simply don't worry about digital copies of my photography. Have at it, go nuts. It hurts me not at all, and it may give you some joy. The world needs more joy.
How the OP feels about *his* work is another kettle of fish, but he's gotten a lot of discussion and why he should charge, and how much. Now he's got a little essay on why he might choose to charge nothing!