Thanks BR, I appreciate that. I'm in the process of publishing detailed information for people who want to build one themselves, but for most people the learning curve will still be fairly high. These materials are tricky to cut (I've ruined my share), and there is also some technique involved in making watertight connections through the wall of the unit. Some of the cuts would be very difficult without a power miter saw and a Dremel tool. I'll be saving money by buying in bulk so my cost to build them will be lower than someone who builds just one or two. For that reason I think the gap between what I can charge and what it costs to DIY isn't all that much. My goal is to create a fair deal for everyone.
I have no doubt that crawfish will devour BSF larvae.