Need recommendations for a soundbar/speakers for mini

[rgG]

The new mini is great, but the speakers are underwhelming. I would like to add either a small sound bar or some small external speakers. USB or BT is fine. I don't want to spend a lot, say under $50, and around $25 would be even better.
I don't need the sound for watching movies or anything, just general sound stuff. The built-in speakers are pretty weak. I wound up using a pair of earbuds yesterday, when I was watching the Keynote, because it was hard to hear on the mini's speakers.
I want something unobtrusive. Everything is brushed aluminum now, so something that blends in with that would be best.

Thanks for any suggestions.