Amazon.com: SparkFun MP3 Player Shield- MP3 decoder- Turn Any Compatible with Arduino Board into a Fully Functional MP3 Player- 3.5mm Audio Out Jack- 0.1" Spaced Header for Speaker Out- microSD Card Slot :
Adafruit "Music Maker" MP3 Shield for Arduino w/3W Stereo Amp (v1.0) | The Pi Hut
MP3 Player Shield Hookup Guide V15 - SparkFun Learn
VS1053 MP3 Shield - RoboticX
MP3 Player Shield Hookup - SparkFun Learn
Adafruit Music Maker MP3 Shield for Arduino (MP3/Ogg/WAV...) : ID 1790 : $29.95 : Adafruit Industries, Unique & fun DIY electronics and kits