I have 5 boxes of the size 2’x2’x15″ high (approx on all dimensions). They are more shipping than moving boxes but if they work for you let me know and I’ll bring them home from work.
I’ve got some sturdy boxes at work that I have put off breaking down as there is often other pressing stuff to do. They are about 2’x2’x15″ high, more shipping box than moving box but they are yours for the asking. I have 5 of them, let me know and I can bring a couple home each day.