I use a simple sports sling bag to carry my car, tx and fuel and some spare batts and a camber gauge.
Accompanied by my tool box where i have some spare parts , glow heater, few tires and other tools. but i`m simple as i don`t have to carry a starter box and a good "precious" TX
I`ve seen some guys with cool and spacious RC bags, looks good, but to me, if only necessary.
Have also seen 1 joker carrying a shopping cart dumping everything in it, with his car right at the top of it. i`m serious.
i hope this helps !