Hello.
 
I've got a bunch of MiniDisc audio recordings I need to digitally preserve. (Someday either the discs will degrade or the player will fail.) The player has both TOSLINK optical and analog outputs. Obviously I want the digital signal. But the cheapest solution I can find is a sound card that costs 100 bucks. You would think there is a USB device with TOSLINK input to stream digital audio to PC that would cost less than the sound card. Also it would be nice if the device would be recognized by the OLD Cakewalk Pro Audio 9, which has served me well over the years. I hope there is someone that can point me to a reasonably priced product that will suit my needs.
 
Thank you.

Don't have a sound card for you, just thought I'd chime in. I used and still use Minidisc for the rare gig. Had quite a few machines die on me. It's good you're thinking along these lines if you want to preserve your data. I've digitized everything I need in case the last machine goes. Amazing nowadays I could do it all with my phone. That is, if I ever get a smart phone.  
 
Good luck. $100 interface doesn't sound like something you'd want to use for something you want to preserve though.