Uline is great. My employer uses them.
Some items are overpriced though.
Agreed. We use them a ton for Fiddleback Outpost - all of our boxes and packing materials come from them. They got us an account manager that helped with customizing the packaging as well. The thing that baffles me is that they charge $20 or so if we want to pick up the materials ourselves (they're just down the street), but they give us free shipping if we order over $300 and the shipping has got to be expensive (we're ordering a lot of boxes, packing paper, cotton bags, burlap bags, etc.). They could save a lot of money of they'd waive the pickup fee. Of course, they could save a lot of money if they didn't include a full color, 400 page catalog with every order - They just released a new one and we already have six copies...