I am a mobile car detailer and I bought two bags from harbor freight. A 20" roll away bag and a 19" bag, think i spent 35 dollars onboth. the 20" i use for products i use most of the time and brushes. APC, IPA, wax, clay bar, various brushes, ONR in a small bottle, rain x, ect. The 19" bag has all of my DA stuff. my Griot grage DA, DA carpet brush, backing plate, wrench, a dozen pads, compound and polish.
I tend to take the 20" bag to most jobs and the 19" bag wheni know I wil do some correction or maybe for waxing. I like the DA to wax with.
problem with bags is that I need a platform to work on. A small table with wheels, but then those waiter carts are hard to put into a car. A table wonderful useful, just not often mobile enough. Maybe a hard plastic rolling toolbox. some are 3 feet tall with wheel, but expensive. These bags aren't perfect,but I love the deep pockets and it helps keep me organized and i can set up and clean up faster.