How much does it cost to fix a gash/scratch on an alloy rim?

I was driving today while it was snowing, and I hit the edge of the sidewalk while I was turning. This is the first time this has happened to me, and I only wanted an estimate or range of how much it would be and HOW THEY FIX IT. I looked at pictures all over the web, and I found this picture that it's similar to what happened to my rim ( http://img303.yfrog.com/i/felge5om.jpg/ ). Thanks in advance.