To Go bags can be a tote, wheeled cart, briefcase or any other portable container that carries your essentials, the tools you need to do your basic work.
For a direct sales retailer, those tools might include product samples, base sales kit, marketing portfolio, netbook, and power cord.
For meetings, your tools might be much simpler: writing instruments, notepaper tablet, calendar and reference materials.
The key is to know what your essentials are, to keep them together, and to keep them ready to go. One method might be to keep your essentials in a basket under your desk. They're ready to pick up and use or throw in your bag as you prep to go.
Wheeled carts are usually around $20 to purchase, but you can find them as low as $12 sometimes - check Big Lots. Most collapsible carts fold down to 3" thick and have retractable handles. Some have solid lids, adding another layer of "totability!" Look for solid construction and good wheels.