Costs

Quantity | Item | Cost | Link

x1 | Arduino Nano 33 IoT | $25.50 | Arduino Store

x2 | Bone Conductor Transducer with Wires - 8 Ohm 1 Watt | $8.95 | Adafruit 

x2 | Adafruit I2S 3W Class D Amplifier Breakout - MAX98357A | $5.95 | Adafruit

 x1 | Adafruit Micro SD SPI or SDIO Card Breakout Board | $3.50 | Adafruit

 x2 | Breadboard Trim Potentiometer - 10K | $1.25 | Adafruit

x1 | Adafruit Micro-Lipo Charger for LiPoly Batt with USB Type C Jack | $5.95 | Adafruit

x1 | JST PH 2-Pin Cable - Male Header 200mm | $0.75 |  Adafruit

 x1 | JST PH 2-Pin Cable - Female Connector 100mm | $0.75 |  Adafruit

x1 | Lithium Ion Polymer Battery - 3.7v 500mAh | $7.95 | DigiKey

x1 | GIANTARM TPU Filament 1.75mm Blue, 95A 1kg Spool, Dimensional Accuracy +/- 0.05 mm | $26.99 | Amazon

 x1 | K&S 3403 Round Aluminum Telescopic Tubing Assortment, 8 Pieces | $5.25 | Amazon 

Total (not including tax & shipping): $108.94