I just found out about an environmentally friendly service called BoxCycle, and I sure wish I had known about them for the many, many times I have packed it all up and moved throughout my life!
I don't even want to admit how much we spent on only a few picture boxes we had to buy to contain our wall hangings... the rest we scored from my husband's job, (empty shipment boxes). But now that I know about BoxCycle, I'll hopefully never have to think about waiting outside a grocery store to ask for slightly smelly boxes for moving again. (That said, my zip code renders a fruitless search when plugged into the site, so I hope this changes by our next move!)
Visit BoxCycle and you can either find used boxes on the cheap (ie: 6 large moving boxes for $1.25), or sell your used boxes to someone else. I think this is a genius service, because more often than not, sturdy cardboard boxes have a lot of life in them, and it's such a waste to not pass them on when so many people are incessantly in need of boxes for moving and storage. It's wonderful to recycle cardboard boxes when you're finished with them, but I like the idea of BoxCycle-ing them a lot more if they're in good condition!