$500 is a pretty low budget for a system. If I needed a system at that budget, and didn't need deep bass, I would probably buy a pair of new JBL LSR305 powered monitors and I'd spend the remainder on the best used Oppo DVD player I could find within the budget. The Oppo DVD players have remote controlled variable volume, so you would have all of the components required for a complete remote controlled CD playback system. You will need to budget a small amount of money for interconnect cables. The JBLs do not have RCA connections, so you'll need an adapter or a RCA to XLR or TSR cables.
Best $500 System?
I have a good friend who is going through a lot of stress including financial and health and misses her music. Any thoughts on a "system" that would play CD's only all inclusive including speakers and amps new or used that might give her decent quality music in her home? she is sensitive to clean highs and does not need very loud or deep bass.