So, I was irritated that the only bitcoin widget was 0.15 BTC, which I think is too expensive for such a trivial function.
So I attempted to make one, but couldn't get it to refresh. I searched for a general image display, and I found Image Loader:
http://gallery.live.com/liveItemDetail.aspx?li=6d48bb6e-a251-4245-96d1-a5d1c9270988

I use the free ticker from:
http://oneminuteslow.com/bitcoin/180-240.png

Add 8 more pixels to the dimensions, and refresh every 10 minutes:
http://i.imgur.com/GS0CX.png

And voilà! A free ticker that updates every 10 minutes.