Took me a good deal more than $5, even with some donated parts, and it look way more than an afternoon. But I learned a lot in the process, and I get a toy out of the deal. Can’t beat that.
It sounds surprisingly good for something driven by a $1.50 amp chip, and with the design incorporating a master volume and a gain control, you can get a pretty robust sound without annoying anyone. You can annoy quite a few people, and I suspect with 2 9v batteries (the circuit can be driven at 18v) it would really hum.
I have bunch more cigar boxes as well, so I may make a couple more of these, perhaps for eBay or etsy.