Plain old single conductor? You can get it for about $11 on amazon with prime shipping.

http://www.amazon.com/Shaxon-SO22-100BK-Solid-Copper-100-Feet/dp/B00IN8341I/ref=sr_1_5?ie=UTF8&qid=1436476724&sr=8-5&keywords=22awg+solid%2C+100%27&refinements=p_85%3A2470955011