best cd player for 300-500 bux

So far used Alesis Master Link ML9600 for near $500 will get you one of the best red book CD playback + recording and possibility of the superior CD24 format you can get the benefits from and finally great headphone output capable to deliver 180mw i.e. drives upto 50Ohm impedance earspeakers without headphone amp(although I'd recommend for the better volume control). It also has digital in-out so you can use it as an interface i.e. DAC as well.
Got one recently for copying my records to CDs (has superior DAC and ADC)... Maybe it's a 'toy' but can't stop enjoying it how it does recordings and playback!

Second for the PS Audio D Link III. At the prices these are going for used it's a true bargain. You need to spend a lot more $ on a cdp to beat it.

Or the MHDT paradesia DAC that seems to get raves anytime it gets brought up. it's on my demo list.

I concur with getting an outboard DAC though. in your price range to get anything that has a chance of being an upgrade, that would be the way to go.

and to add, getting another player just for a removable power cord makes no sense to me.

Cambridge Dac Magic.......$350 to $375 at Audiogon.