I was going to jump on here and say there's no way to tell from a picture, you need to put it on a bike with a chain and try it out.
Then I looked at the picture.
Compare the tooth profiles from the middle cogs (4-7) with the smallest cog profiles, especially (because they're so visible) around 9:00. I'd say it's worn out. Worth scrap for the metal, which still isn't much because it's the wrong alloy for beer cans.
Really, buy a used cassette? Why not dirty underwear instead?