By doing work for free you will probably hurt yourself more in the long run. People think that if youdon't charge money or not enough that you are probably not that good. People are usually under the impression that you get what you pay for, and in most cases this is true. To get experience I would suggest going around to some professionals you see working these events and ask if can tag along, and maybe be a second shooter. Sometimes the person will say yes, and sometimes no. Sometimes they might pay you a little something, sometimes not. But, I believe by doing work for free you will end up regretting it later. Your time is worth something just like anyone elses.

Thats my 2 cents-Z