I've been trying to use some of my "goodwill knits" to make space.
I had this blue ribbed-knit sweater I used to wear all the time in high school. So it got a second life, this time that of a boy's sweater vest.
I actually bought 5" of brown ribbing for this project. I usually just cut up other knit I have, but I couldn't find any brown shirts in my stash.
Not that you can see it, but I also added a 2" ribbing band along the bottom, as it was just a shirt hem, not a nice sweater bottom. Sewing with the knit sweater can be a pain, as it can stretch a ton, and become deformed as you sew. To avoid this, I sewed with my tension at 10, and stay stitched the sweater neckline before I sewed the ribbing on top to help stabilize it from stretching huge.