I just checked out Smith & Hawken's web site and sure enough they say $40 shipping for the $20 single layer, but I checked what the shipping for a complete Biostack (3 layers) and it is $15.95. Someone at S&H has gone crazy. I've sent them an e-mail to ask what's going on. As I said in my message, in July I sent a Biostack and an extra layer to a friend in New Hampshire for $127.95. As to the "they" which you say is the Tarrant County Cooperative Extension. Have they published their study? I'm very skeptical. I recommend putting compost piles or containers in the shade. But this isn't to protect the plastic containers, but to protect the composting person from the sun.