I started my stash 20+ yrs ago. In the beginning, and now carried on as it's a big help.
I bought Plasitic notebook sheets that are used by photographers to hold 32mm. slides, one for each color.
Into each pocket I put a folded card that fits the hole. On the front of the card I glue (staple) a square of fabric. On the back is written the amt. of fabric, it's cost by yd., total, date & where purchased, mfg., designer, theme. When I use any, I note how much remains. Inside I can write anything special (quilt it's for, or a larger piece of fabric if helpful. Can take the sheet with the color I need when I go shipping.
This all started because I needed a backing for brown quilt. I found out later I bought 7 yds at 2 sales of brown with white dots for that quilt. (total 14 yds.)
The fabric was stored in Apple Boxes and marked as to color (later Plastic Boxes). I've moved 3 times with my stash (once had a Yard sale in Calif. (invited all the Guild mbrs. made $1,000+) And now look for fabrics I know I had.
I moved to VA and live w/ my daughter, because the stash takes up so much space, I rent a Storage locker for it ($100. a mo), which is 7 miles away- "very convenient"
"BEWARE Quilting as a Hobby can get expensive. CECELIA