During open house last year came up with the idea of handing something out that was promotional to our shop. It had to be something education to electronics, of course cheap,easy to manufacture and require no soldering iron to the end user. I came up with this solution:
I used Traxmaker 2000 Pro (yes I know it old but it works really well and works in WINE) and one of our T-Tech 5000 milling machines. If you would like the gerber files email me. With all three milling machines running we can produce about 300 boards an hour.
I used machined IC pins and solder them in so all that was required to the end user is to plug in the components. Included would be the PCB with pins soldered, 1K 1/4 Watt resistor bent and cut, LED cut and 9V battery clip that was already pre-tinned from the factory, instructions and a small plastic bag.
You could expand this idea into many thing like a larger resistor to show different brightness of LED verses current, Bi Color LED's, small buzzer, etc.
BOM Break down
PCB $.02 (.5"X .65" can fit approx 256 on a 8X10 board)
LED $.035 (in qty of 1000)
Batt Clip $.18 (in qty of 100)
1k Ohm $.00741 (in qty of 5000)
IC Pins $.15 (really free from donation)
Total cost $.40 Each
I could probably get cheaper parts on E-Bay but my school only allows Net30 only so were kind of limited on were we can get parts.