I had my own system that was working well but carrying it up and downstairs is a hassle. My “caddy” system was a target bin that is pictured. Everything in the bin (even that amount of diapers) fit into the caddy and had more space to go!
The handles are perfect to carry it too. I bring up 4 bottle with 4oz of water in each bottle and then two formula holders. That takes up a lot of space and I didn’t have room to put bibs and spare set of clothes. Now I have space to put them! Very happy!