I'm sure this is a newbie question, so apologies in advance.

If an 48 kHz dac can upsample to 24/192, can it also play hi rez music natively? I was checking out a site that offered hi rez downloads (24/192) that could only be played through a computer-based music server. They recommended a specific DAC that had a retail price of $5K. Ouch! I have an relatively inexpensive DAC that is 48K, but it includes an upsampling daughter board that is selectable up to four times oversampling.
I guess I'm finding some of this playback terminology a bit confusing. Can someone clear things up for me?