Man that stuff is pricey. If I build im just going to go with wood or melamine. Think it would be more cost effectiveYou can also buy the material and make your own. To give Kages credit, the material is expensive. You can purchase here: https://www.onlinemetals.com/en/buy/plastic/0-5-hdpe-plate-seafoam-marine-board/pid/21742
They sell it as seafoam marine board. It's an extruded, air filled HDPE.
Kages does not heat seal the edges, they just cut and drill holes for screws. It works somewhat like wood, but you have to be rather careful not to strip the plastic when fastening, as it is weaker than wood. OnlineMetals will also sell you the clear plastic sheet to make doors. I was lazy enough not to do this for my Tegu's cage, but I have used it for other custom projects. Pretty decent.
Agree with LadyLuck on this one. While some people use wood or melamine as a cheaper option, most of them end up coating the pieces with several layers of a water proofing solution such as epoxy or even various forms of concrete, which ends up also being pricey. Also many times this method only lasts for several years before a leak or rot inevitably occurs, and then you have to deconstruct and try again. Kages and options like that are indeed expensive, but the tradeoff is that they save keepers the headache down the road that usually comes with cheaper optionsMan that stuff is pricey. If I build im just going to go with wood or melamine. Think it would be more cost effective