I have a very large plastic utility/tackle box that has a shoulder strap on it. It holds bags and bags of patches, bottles of solvent, small tools, lots of jags and brushes, some parts, screwdrivers, pistol cleaning rods, cleaning brushes, cut hardwood dowels for cleaning, and quite a bit more.
I don't buy kits. I buy what I need and probably what I think that I'll need one day...