I've found a very small selection at the used record shops. In fact, all but one of my hi-res discs have been bought at such places. It's worth checking out, if you're the type to go to these shops often.
I'll never forget going into Future Shop, asking the salesboy in the music section, "Where' the hi-res audio section?" and seeing the blank look on his face! He truly had no idea what I meant. I pressed further: "You know, SACD and DVD-Audio?" The bulb went off: "Ohhh . . . audio on DVD!" and took me to the concerts on DVD section. I had to educate the poor kid on what hi-res audio really was, and even then he didn't know if they had any. When I finally did find the hi-res audio section, I was shocked at the (Canadian) prices: anywhere from $30 to $45 for a single disc! No wonder hi-res isn't really succeeding! The prices are ridiculous, the sales staff didn't know where in the store they'd be, didn't know anything about the formats!
One salesguy at a Future Shop was trying to convince me that hi-res audio can pass through optical or coax cable no problem. Poor guy -- he was really floundering, trying to sound like he knew all about it, when the opposite was true. Again, I had to educate him on All Things Hi-Res.
When I mention hi-res audio to my friends, generally their faces go blank. They have no idea what that means. Then I played Dark Side of the Moon (SACD) at a small party at my place (on my admittedly low-end equipment). The look of shock on their faces -- not to mention the quiet "wow"s and "whoa"s felt darn good. My girlfriend has no idea why I love it so much. "But it's multi-channel!" I say. "It puts you right inside the music! And even the stereo stuff SOUNDS so much better!" But she doesn't really hear it. I bristle when I hear the audio limitations in a 128 Kb/s encoded mp3, but it sounds just fine to her. And I suspect most people are like that. Sigh.