My stash consists of yarn that was on sale, leftovers from previous projects (sometimes whole skins), and yarn that I'm preparing to ues. So you can buy as much or as little yarn as you want. But since your new to knitting you want to make sure it's yarn you'll use. I still have yarn at the very bottom of my stash from when I was just starting years ago.
Tabitha and the Shelties
tabsheltie7 on Ravelry
"Did you hear of the pregnant cat who ate a ball of yarn? She had mittens!"
"Went to my doctor, he told me I needed more fiber. So I stopped at the yarn store on my way home."
“SABLE- A common knitting acronym that stands for Stash Acquisition Beyond Life Expectancy.”