Canna Coco bricks are pretty cheap. I like them a lot. And you can reuse it in multiple grows. So I think it's pretty darn cheap from a cost per grow perspective. And being a chronic over watering guru who has had gnat issues in the past I like coco for its drainage and ability to dry fast. I've done peat in HP promix in multiple grows, soil once and coco a couple of times. Coco to me is the best medium for a guy like me. It took me a long time and trials and lots of errors to come to the conclusion that coco is a great medium. And its cheap! @slowandeasy told me coco was the best a long time ago, and I finally understand that.