I use duffle bags for a lot of stuff, I find them at garage sales for a buck or so. I also have a travel pack (luggage bag with a belt and shoulder straps that come out of a zip pouch.

Look into getting a wheeled cart that you see people pile luggage on in an airport. I have one that folds up to a very small size (3-inchs round by 14-inches long) it’s called ClicKart and again it was a few bucks at a garage sale. I can get 3-duffle bags on it before it feels like it’s overloaded. Don’t forget to add a few bungee straps to hold stuff to the cart.