And to kick things off, I already have two of the cans: Hawkeye and Iron Man. I picked them up at Walmart last weekend.
As I get the other cans I will update this post with those stories.
05/02/12 Update - I found this Hulk can on the side of the road on the way home from work today. I'm halfway there...
06/25/12 Update - Dollar General had a Captain America 6-pack today, so now I have it.