USPS. I just asked and they sent me a bunch of free boxes. Also, if you go to grocery stores they throw out tons of banana boxes, these are perfect for holding books and various other household belongings.
Edit: By the way, I ate an apricot today, then I cracked open the pit to eat the seed. It was almost a tasty seed, but it was also quite bitter. So it wasn't a tasty seed. Afterwards I went to read about apricot seeds on the internet and found that if you eat too many lethal amounts of cyanide will develop in your body. On the other hand apricot seeds are high in Vitamin B17 which some theorise may prevent cancer.