I doubt it. Even the ACM conferences I've been to have fees around $500. Putting on a conference is not cheap. They have to rent a large amount of space in a high demand building for a weekend and feed everyone who comes.
Think about it this way: a medium sized wedding reception in a nice hotel can cost around $20,000. That wedding reception takes up one large room and lasts less than five hours. Now imagine taking up that entire floor of the hotel for 96 hours. It won't be cheap.
Right on, even makes you think if Joel Spolsky product's are the money-makers, when the conference has a sub-line : "A Joel on Software Conference"! ( http://www.businessofsoftware.org/ )