Interesting and quite ironic post that asks - Is Jimmy Wales Worth $300? - Jimmy Wales is the founder of Wikipedia and his talk is "Challenging how knowledge is created." It is ironic to be asking whether his talk is worth money? And, there are some links to his presentations that are quite good in this post:
his presentation on TED Talks, a recent one - Jimmy Wales Gives Talk on Free Culture, Transparency, and Search - from earlier this month, on Cnet (excuse the compulsory Microsoft ad at the beginning) and Vision: Wikipedia and the Future of Free Culture from Fora TV.
But there's also a much bigger question going on whether it's worth going to conferences, events, talks, etc. when there's so much that's freely available.