Not that I can see. There’s maybe $20 of components in the amp part, and the arduino uno is about $25. Building the amp will be a bit time consuming without having the printed circuit board but it’s a simple circuit with only one small chip (at least on the schematic I found) and “prototype boards” are available that plug into the arduino board. I think the cost probably represents the time involved in making the parts like the coil and the various mechanical bits.
I guess I have to ignore this thread this otherwise I’ll be forced to build one :lol: