So why not use what you have? Smartphones start at 20 bucks.
For under $50 (or less!), which is the best MP3 player that would sound good through a large speaker system. Say, for an event of approximately 200-250 people. It wouldn't need to be made recently. Reliability/quality of sound is more important than flashiness. It would only need to hold two hours worth of music. Also, is there a way to make sure the music (consisting of one, single track) doesn't accidentally get deleted by whoever is manning the audio? Thanks in advance!