I ordered the $19.50 LL Bean backpack in Brambleberry too!
I got it last week. It is a pretty thin nylon, but appears durable. It was the perfect size for running shoes and gym clothes and it fits snug to my back. The waist straps are very long, though and when I wasn't using them I had to sinch them up in the exterior straps. So far I'm happy with it, though.