Hi Sean.

It depends on who you offer the free service to. If it is to family and friends, then it isn't such a bad idea. If you offer it to anyone online, then you undervalue yourself and your work.

I got a great experience doing an internship with my college's Athletic Department as a photographer, but it didn't pay anything (I got credit, but that isn't really good compensation in my mind as I had to pay for that as part of my tuition). When I graduated, I had to twist some arms in order to get paid.

If you plan on shooting at events, you have to take into consideration your time, the cost of your transportation, the cost of your equipment, and how long it will take for you to do your post-processing. Is building your portfolio worth giving away your service?