Sometimes it can be difficult to find an inexpensive way to store and protect your knives in an organized fashion.
I have found that pistol magazine storage pouches work extremely well. The storage pouch you see in these photos was purchased from MidwayUSA for ~$23 and has 8 pouches.
In these photos, you are looking at a Kershaw Blur, a SanRenMu 763, a Benchmade Mini Griptilian, a Spyderco Catcherman, and a Spyderco Endura 4. These should give you an idea of what will fit and what won’t. The storage pouch was designed for double-stack pistol magazines up to 5.5″ long.
There are other models for longer knives(or magazines). For fat knives, I would recommend a pouch designed for AR magazines.
Yes, there are other magazine pouches that may work, but I recommend the California Competiton Works pouches. The stitching has held up to my carrying them on road trips across the country, numerous range visits, and general rough handling. These pouches are often carried with a full load of full magazines. With my XDm9 mags, that means >150 rounds. Not an insignificant load.