Piezo Buzzer [PS1240] : ID 160 : $1.50 : Adafruit Industries, Unique & fun DIY electronics and kits
MCKPR-G2310-4128 - Multicomp Pro - Transducer, Piezo, Buzzer
Amazon.com: Buzzer Piezo Speaker- 6PCS - 20- B Mini Active Piezoelectric Buzzer DC 3-24V 85DB Small Enclosed Piezo Electronic Buzzer Alarm with Wires, Black Piezo Beeper : Electronics
Large Piezo Alarm - 16 Tone - COM-13939 - SparkFun Electronics
Passive Buzzer module 5V Piezo Speaker Play Song Melody Module for Arduino