Movable Toy Stationary Holders?

I've always loved toys, and I would like to do my part in recycling. Somehow, along the way, I decided to make use of those good cardboard boxes that I've collected, and make them into something useful, yet "play-able". Thus came the idea of making stationary holders that are movable... like toy cars, yet can carry some stuff in it... So made these...

I know they are not perfect, but am very glad that I made them. They are my prototypes, and thus will continue to 'polish' up my skills and hopefully the next few 'toys' will be much better...