For organizing my smaller bottles of flavorings (sample size to 30mL) and other DIY materials...I use a sectioned, plastic cases, with clear lids. They're made by Stack-On Products, co. and they're very sturdy! Shapes are rectangular (about 13" x 17" x 3 3/4" tall) and longer ones that aren't as wide that are about 18" x 5.5" x 3.5" tall. Some have movable dividers so you can customize the size of the sections. Others have bins in them that are also movable within the case. They're usually black and school bus yellow...sold at Harbor Freight Tools, Tractor Supply, etc. for anywhere from $9.99-about $14.99. When found on sale they're about $5.99-$11.99 each. I love mine!
(They could also definitely be used for storing/organizing small tools, rebuilding materials, a good number of tanks in your rotation, etc., too though. Not just for a mixing kit!)
Larger 4oz. and or 16oz. bottles of flavorings that I use to refill the smaller bottles and vials...are just stored in used Priority Mail boxes that vape mail has come in, and are kept in a dark closet.
For storage of tanks, small tools, coils, batteries, etc....it's hard to beat one of those metal and plastic storage drawer/bin type of things. They're not flat cases, like the divided/sectioned ones I mentioned above. These stand upright, and they're stackable. You can find them with 15 drawers, 30 drawers, 48 drawers, 60 drawers, etc. They're basically a metal outside frame/case with the bank of plastic, pull-out drawers. Room on the front of each drawer to put a label on it to indicate drawer contents.
I've got WAY too many new tanks, boxes and bricks of coils, etc. in my "stash" to use one of them for those. But for organizing a smaller quantity of those things that are in use frequently...they're ideal.
