Now, I could be wrong on this, but for me, it was cheaper to get my supplies at a couple different places rather than all at the same place.
Online Uhaul had a "deal" for a 4 bedroom household for 389.66. It has alot of boxes and equipment, but I didn't need all of what they were offering.
So I spent about $100 on boxes and then went to Amazon.com to get my labels, bubble wrap, stretch wrap, paper, tape gun and tape.
Between the two places, I got more then I needed for a total of about $200.
Yes, it's easier to get it all at once, but you might not need all of what they are offering AND you can spend more money on specific things that really do help.
For me, the things that I LOVE LOVE LOVED were the stretch wrap, and labels. See what works for you!
Do some research. Pinterest has some great posts and ideas as well. - Rejoicing in the Present