But if you are asking about the cost to produce, the financial resources of the inventor are finite - no more than a few million $. And in Q&A sessions he mentions making around two thousand prototypes. Even assuming these were largely recycled, the implication is that they are not terribly expensive to build. The prototypes shown in demonstrations to date are quite small even with the thick shields and pipe apparatus.
They have also worked reliably in the demonstrations. This suggests the technology is not terribly complex and is robust even in the prototype stage. Again, this suggests the devices will be fairly simple and cheap to build - regardless of what they can charge for them.
It seems absurd, but I an others here have been tracking this story since January, and it has not been debunked (but is rather running in the opposite direction.) Crazy.
"As much as the market can bear" is not usually the price-point that maximizes profit. For the first couple of years at least, you want the price-point being low enough that your product gains high demand. It is better to make $100 per unit on a hundred million units than $10,000 per unit on a few thousand units.
If it were me, I'd price the e-cat at a price point where it becomes very worth-while to convert existing coal-fired power plants to e-cat, with a discount to the first dozen customers. You KNOW there will be glitches in the first years, and it will take some time to get them operating reliably, and you want your initial customers to still make money even in the face of glitches and breakdowns.