I just realized creating compost fits the bill!
But I was thinking about how helpful old pantyhose is. You can cut across the "limb" to make various size bands or use an entire leg as a quick fix bit of rope. I use it the most for securing branches to trellis or cages. It is gentle and will stretch as the plant grows. I have some pieces which have been used for at least 15 years!
Whats your favorite frugal tip?