Have you heard of "1/2 Price Boxes" in the Houston area? They're a fabulous resource for boxes of any kind, as well as moving and shipping supplies.
I went to the Pearland store and got 25 boxes (20 small and 5 large) for only $25 -- you can't beat that price anywhere that I've found if you're buying boxes for anything. The gentleman running the store was so helpful, and so sweet ... I've packed up all those boxes and will be headed back for more.
They also sell bubble wrap, peanuts, tape, tape guns, packing paper (blank newsprint), moving blankets, peanuts, foam, stretch wrap ... I'm sure there's more that I can't think of right now.
I found them on the Web, which is why I'm posting about them here. I'm not affiliated with the company, nor will I get paid for this endorsement, but if you're in the market for boxes or shipping/moving supplies, I highly recommend them.
Here's a link to the website: http://www.halfpriceboxesofhouston.com/index.html