> tens of hours on building it plus over $300 in parts
In other words, quite inexpensive.
To you, sure. To others, maybe not. Whether something is expensive (in money or time) is relative.
Relative to other hands on, high tech educational experiences would be a smart way to think about it, if you insist on adopting the sucks in a long hit of marijuana smoke “everything is just relative, mannnnn” attitude.