Greg Mitchell, chair of the Arizona Section of the the Association of Environmental & Engineering Geologists (AEG) informed me that student membership to this professional organization is now free.
The Arizona Section has grown dramatically in the past few years and holds great monthly dinner meetings and talks. "One of the Arizona Section’s biggest annual events is Student Night, where students and professionals get together to network and students have the opportunity to give formal presentations or do poster sessions on their work and research."
Unfortunately, the links to the student application on the AEG web site is broken but until they get that fixed, try emailing them at aeg@aegweb.org.