Hello Mr DEB, didn't you hear me?
A transistor does nothing without a collector load resistor. A piezo is not a load resistor, it is a capacitor that does not conduct DC current.
A DMM can measure 50Hz or 60Hz accurately. But it cannot measure 10kHz to 20kHz voltage or current without a huge error. It will show a reading that is much too low.
Or maybe you measured the DC current drain of a Cmos 555.
I can't remember if you ever made a push-pull amp that works.
EDIT:
RadioShack knows nothing about electronics or electronic parts. Usually they spec the weight of an electronic part instead of its technical details. Half of their parts don't work properly anyway.