Parts for something like this? $1 ESP32, $5 LCD, $2 lithium battery, $5 3D printed case. Assembly? (Depending on quantity) maybe $5. This is max $20 to build.
I guess if you want something like this but don’t have time to build it it could be worth $100
I guess if you want something like this but don’t have time to build it it could be worth $100