The DFPlayer Mini MP3 Player For Arduino is a small and low price MP3 module with an simplified output directly to the speaker. The module can be used as a stand alone module with attached battery, speaker and push buttons or used in combination with an Arduino UNO or any other with RX/TX capabilities.
https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299