Just scored the 20 pack. It was at Target by the DVD's just as others have found. Various other Metalfigs also.
Very interested by the uncoming wave 2 singles preview on the back even if there's only a couple figures that aren't already available. I'll snap a pic and put it up this week if no one beats me too it.
As I haven't seen an of the Wave 2 singles in stores yet, I think I've finally managed to acquire all the currently available figures!