I really like the Rigid brand crate from Home Depot in the tool section. It's about $20 (or $15 on sale), has a solid bottom to keep water off my cars carpet, has folding handles, and is open on the sides to allow gear to dry. Easy to setup for spools storage.
RIDGID 22 in. Pro Box, Black-226036 - The Home Depot
Unfortunately, the Rigids don't work for me in the correct combination of internal and external dimensions.
I went with the DeWalt Tough System boxes:
ToughSystem® Mobile Tool Storage System | DEWALT
For the holidays, Home Depot was selling this 3-box stack for $100:
DEWALT ToughSystem DS450 22 in. 17 Gal. Mobile Tool Box, DS130 Tool Box and DS300 Large Tool Box Combo Set (3 Components)-DWST08250203130 - The Home Depot
I got 2-sets.
The big wheeled base box (DS450) is too tall to fit
under my sleeping platform (with all the rest of my equipment/cylinders/suits, etc.) in my van and I will have to see if it can get it to fit-in elsewhere before starting to use it for camping & diving trips. Worst-case, I'll use it for tools.
With a little trimming of the internal ribs, the mid-sized box (DS300) will fit 3 reg-bags (or 2 and a OrcaTorch D620 box) vertically on one side, leaving about 1/3 of the space for masks, computers, and other smallish items.
The smaller DS130 box will get used for tools, spares, etc.
I then got their handled open tote (DWST08206):
ToughSystem® Tote with Carrying Handle - DWST08206 | DEWALT
https://www.amazon.com/dp/B07GLB1FVP
which I will use for reels, spools, bag, etc so they can easily dry. I may also use it as a boat-tote for local offshore dives instead of a milk crate. It will be easy to drill some holes for lines if I want
For reg-bags in the cases I've got several of the Edge/HOG bags.
Edge Regulator Bag
DRIS was selling them for $12.75 for the holidays, but still only $17.