Adafruit Music Maker MP3 Shield for Arduino (MP3/Ogg/WAV...) : ID 1790 : $29.95 : Adafruit Industries, Unique & fun DIY electronics and kits
SparkFun MP3 Player Shield - Protocentral Electronics
Prof. E. C. Kopff, “The Shield of Achilles,” (MP3 Download) – The Fleming Foundation
Cytron MP3 Shield
VS1053 MP3 Shield - Elecrow
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 1788 Music Maker MP3 Shield for Arduino 3W Stereo Amp | Rapid Online