SimLego:
I'm probably very spoiled, but I don't find that module very cheap.I can buy a car mp3 player/transmitter with USB connector, SD card reader, remote control and decent sound quality for maybe $4.00. But just an mp3 player without FM transmitter, without remote, without USB but with Arduino compatible input pins instead of buttons is $19.99. Why? I guess part of the explanation is the fact that they don't make this in the same quantities. But yet, $20?
it's cheaper compared to other mp3/wav sound module for arduino.
And it seems obvious that this module is more expensive than a normal mp3 player because this can be controlled by Arduino (or other MC) as needed trought input pins... the basic principle of arduino ..