There are a lot of these "code schools" that teach you iOS or RoR development in 8-12 weeks. They say that they can guarantee you a job as a graduate but the program costs anywhere from 4-12 thousand dollars.
Conferences cost a bit less than that but are still very expensive. Most run around 2 thousand dollars for three days including lodging and food. Sometimes airfare can tack on another grand or two if you are traveling overseas. I've never been to a conference, but they seem like a great place to meet other people in the industry (aka network).
TL;DR Which is a better investment? Lets say you have four thousand dollars, where would you spend it? What conferences/schools would you look at?