1. Reclaiming yarn: thrift store sweaters
Recycling sweaters is not only thrifty, it's also eco-friendly! You can buy a sweater for just a few bucks at a thrift store, and turn it into several pounds of yarn.
The right equipment - a swift, a ball-winder, and ideally a small yarn scale - can really be a godsend for this project. Learn to examine the seams for indications that you have the right sort of sweater on your hands. Be sure to wash your sweater thoroughly before you start.