How much would it cost to produce an already designed handheld device (super-small batches)?

Question

ARM

How much can it cost to produce the simplest portable device (a cheap character screen plus a couple of dozen buttons and can be a slot for a memory card) + either usb or bluetooth / infrared based on some stm32 or arm chip (nothing more) for everything you need and ready schemes, files, documents, etc. (i.e. if, for example, everything has already been developed and tested), provided that the order is a minimum lot or 2-3 devices in general!
Let it be a monolithic single board, with all the necessary connectors soldered on it (buttons can be stupidly soldered directly to the board) ... and if this noticeably increases the cost of production, without a battery, etc. charging management. The case is probably without options - 3D printing for outsourcing (it is clear that the choice is between powder or printing plastic that hardens on UV).
The goal is to develop and upload to the open source a hardware wallet (more precisely, a device for storing private keys and signing ready-made bitcoin transactions issued by a computer) with all the necessary documentation, schemes, and auto-assembly scripts with manuals (so that everyone can at least check that the files sent to the factory are what is described in the diagrams).
Such things, I think, should simply be completely open source hardware, and not just software or, moreover, something proprietary. And even more so, wholesale production is also unreliable, because you have to trust this manufacturer (and only the final assembly plant, but they have to be trusted anyway).

Answer 1

I’ll say right away that it’s better to do either 3-5 projects at the same time or in a batch of 5 pieces (the price tag for one product will be up to 20-40% less).
So the manufacture of the board ... the most unpretentious (cunning) 2-layer will cost from 2000tr (there may be 5 of them on the textolite, then I cut it and am satisfied, but all because the manufacturer is not thrilled to cut small pieces of textolite for each and sit in scraps then with which it is not clear what to do and their sizes and parameters can be seen at the same "Resonit" the Chinese have a little cheaper, but the search for those who will do what they wanted to see the first time will take a lot of time)
Much can be said about the installation, but the truth is that for such a small series it is better to master the hair dryer yourself. And the diodes will be turned as they should and the circuit is precisely checked before starting (I already burned a couple of stones, so now everything is done by myself, sometimes only the actual installation of the stone and I ask you to do it.). So, on average, the price for mounting an element is from 5 cents to 20 cents, not counting the stones, there can be something different every time. Our dealers are always different. there were both 1p per element and 15k each, but the series should be 1000pcs.
2) 3D printing... here or someone familiar with a 3D printer, which is ideal. Or similarly apply to offices, but there is a dense forest. Orders are taken from 2T.R. but in fact a simple layout can cost 3 and 5, and the same but from different companies. I myself have not yet been able to find someone who, according to SLA technology, would be the most acceptable in this matter.

Answer 2

If a 2-layer board is enough for a project (5 by 5 cm maximum), then you can order a dozen boards from the Chinese and invest with delivery of $ 20. If the board is 4-layer, then $ 80. Collect 2-3 pieces can and a local hobbyist soldering iron. That's based on this and consider.