These plastic cases are injection-molded, not blow molded. I'm guessing that the AA case costs in the neighborhood of $0.50 USD each based on a two-cavity 200 ton press with a 30 second cycle time and clear HIPS material. That's assuming there is no wastage, no setup charge, no shipping, no tool amortization, etc. Just press time and material time. And I'm assuming that it's an optimized tool with nice, thin-walled plastic.
That is *not* "cheap." That is at least $1.00 to $1.50 in product price by the time you factor in distribution and retail markups. You have to realize that they have this expensive case *ON TOP* of the retail packaging. I have no idea of what they were thinking with that. Packaging is already expensive.
Then there's the type of tool that needs to be purchased. This is where they're really going to feel pain. They surely budgeted the part price with a multi-cavity hot-nozzle tool for no waste and no trimming. Well, kiss that plan goodbye if they aren't planning to dig deep in their own pockets. Now, they're down to a cold-runner tool with sub-gates that generate maybe 25% of the part weight as scrap that they don't dare regrind back in if they don't want black specs showing up.
China used to basically give their machine time away for free. I don't think they can do that any longer. I think that a quality molded part will be cheaper there, but not half or 1/4 price like it used to be during the bad old days of the Asian financial crisis.
For anyone that hasn't done it, running clear plastic at a custom molder that runs every other kind of plastic through the same machines ...
... well ... it's a nightmare. An absolute nightmare. There will be black specs everywhere. The scrap rates just go through the roof. You need a molder that has machines dedicated to clear resins that have a very strict cleaning regimen for the extruder. There are also a lot of cleanliness considerations in order to prevent contamination. I won't bore you with them all.
And to me, it looks like the case for the Batterisers are model-specific. There's no way they're stuffing a D-cell in the AA model they have shown.
Like I've said before, the worst punishment there is - is for Batteroo to actually have to manufacture and ship.