I’m in a similar situation to Veronika… I don’t have a huge stash, but always enough to keep me busy.
My storage space is limited, so I prefer to buy materials on a project-by-project basis.
Just the other day, a friend gave me a bag of yarn scraps that she would otherwise have thrown away.
I’ve already used up the first yarn from it as a top-down raglan for this bolero.
I have no idea what kind of yarn it was—it was really thick and didn’t come with a label—but I crocheted with a size 10 hook until I used it all up.