> 100% profit margin [..]

That’s not how these things work

Apropos open electronics, one of my most treasured toys is a Denshi Blocks electronics experiments kit, with a synthesizer chip in it.

https://en.wikipedia.org/wiki/Denshi_block

There are professional versions of the Denshi block, used in engineering schools in Japan in the 80's/90's (as I recall), to lay out circuits and serve as a test-bed for student lab work:

https://www.denshiblock.co.jp/whatdbk.html

(See also: https://www.denshiblock.co.jp/seihinindex.html ..)

In my case, it's just a great reminder of the 70's, and how bright and shiny the future used to seem. Its also a pretty fun little woo-hoo-bonky-boing synth toy, now and then ..

I would have to wonder if there aren't pro blocks in that store somewhere, probably in their own neatly labeled section ..