I ran into a similar problem from U haul. So, instead I went to their U Haul Boxes Exchange Forum and met someone from my area who was selling their old u haul boxes and saved a bunch of dough. It is so much better than u haul itself because it organizes everything geographically.
I don't appreciate how u haul sells new boxes as I like to recycle, but this post on their forum was great
Variety of U Haul Boxes For Sale
When I went to U Haul's website I went to the forums and found the u haul box exchange after I purchased u haul boxes and found many boxes that I could pick up quicker for much cheaper. I hate it that U Haul sells boxes new but doesn't advertise much about this great box exchange.
Review about: Uhaul Website.