These, my friends, are sundry bags--also known as cosmetic bags, toiletry bags, etc. They are perfect for WIP organization for several reasons:
1. They are clear, so you can easily see which project is being stored in that bag.
2. They come in all sizes, so you can use small ones for small projects and large ones for large projects (and for really large projects, you can use clear sweater storage bags).
3. Most are small enough that you can tuck them into a tote bag for on-the-go crocheting--and you'll know you have all your supplies with you!
4. Many have zippered pockets for keeping smaller items like hooks and stitch markers.
And they're affordable, too! They even come with free shipping on Amazon.
Now doesn't that look nicer than a pile of yarn in the bottom of your bag?