I use home made foam nucleus hives with waxed cardboard boxes inside and milk crates outside, with Coroplast covers. I get the materials for free at DumpsterMart
The only cost was building the heat controller for the hot wire bow to cut the foam. I bought a variable AC transformer ("Variac") and mounted it inside a 4" aluminum tube with an isolation transformer, a lighted rocker switch, a fuse, and a +- plug for output to the bow. The funky plug is so someone doesn't plug the bow directly into the wall socket and melt the wire, lighting the barn on fire, etc.
A smarter setup is to make a Wheatstone bridge with the variac in the middle - you can put out more constant heat at the wire very easily that way, leaving beautiful surfaces.
The hotwire bow is made with a frame that looks like a big, wide letter "H", with a hinge connecting one leg to the middle cross bar. A cable, a turnbuckle, and 50-lbs spring scale add tension across the top. The .020" stainless or Ni-Chrome wire spans the bottom (I made pointed, 1" diameter x 1.25" long Teflon beads for hand-holds), and is electrically connected by alligator clips (wires run up the legs and one goes across the cross-bar) to the heat controller through the +- plug.
Another good feature is an elastic band suspending it from the ceiling so it holds most of the weight and gives you just the right amount of control. We make plywood triangle templates for cutting straight edges ("dicing" is the term).
Many other foam cutting devices exist - bandsaw types made with a rat trap for a spring, a planer type makes sheets out of blocks much more efficiently than dicing, etc. Many other tools, such as: a deadman wire holder; shaped cutting templates; hot tubes and hot rods for "drilling" holes; etc., can increase the versatility of a foam cutting shop as well, which is getting off-topic, but not if you can figure out how to use it for bees...
Please beware that some foams (not polystyrene) give off toxic fumes. Wear safety glasses, a face shield, and light cotton gloves when operating hotwire equipment. Use a minimal amount of electric current when cutting - hotter is faster, but it breaks wires, and creates less fumes. Stainless .020" wire takes about 55 lbs tension at low heat and cuts relatively well. It sees a lot of breakage at 60 lbs tension. Tension is not super-important when cutting straight, flat cuts, so set it at 50 lbs and go slow.
There are many other designs, and many of them work quite well. Need help? Someone at a model airplane club or model store should have one, and plenty of ideas, too.
