Update.
When I said "cheap" I was thinking around a hundred bux or so. But I found an eBay deal on a Behringer UCA202 which I figured I'd try. What's to lose at under $25 including shipping?
Well, right out of the box, while it may not be a giant-slayer, to these ears, it's a significant improvement over the sound card in my desktop MAC. The Behringer is a new unit and I'm eager to learn if some break-in hours will improve the sound even further.
Spotify streaming classical music has more air and detail with tighter bass. Imaging is improved. There is simply more "immediacy."
I love this hobby- especially when I find insanely great value for money spent.