I want to take the Certified Irrigation Contractor exam, but I would rather pick up used copies of the study material than pay full price for the books from the IA. Anyone have a good idea? (there is nothing on Amazon or eBay, I have been looking for months). Also, is it worth it? I almost never get asked for credentials, and I am wondering if it is worth the investment. My background: -3 years as an Apprentice Journeyman Plumber (throughout high school). -1 summer as a Sprinkler Repair Foreman for a full service landscaper. -1 summer as an under-the-table sub-contractor for doing repair and upgrades for four lawn mowing companies. -1 summer at Red Butte Botanical Garden doing irrigation and horticulture. -1 year at an irrigation supply warehouse managing their retail sales and designing new systems for small/ medium homes. -7 years doing repair as a part time job (about 10-20 hours a week during the summer) for supplemental income.