GPS - Speaker

We´ll use a 12mm diameter, 0,7g weight speaker (254-PS600-RO)
http://www.mouser.com/ds/2/209/KT-400402-194153.pdf

Price: $2.58 @ 1pc ($1.78 @ 100pcs)

As we just need to play some low quality tone alerts, we´ll use the simplest one-transistor amp driven from a MCU GPIO.

Speaker schematics