Found them on closeout at Wallyworld this week.  

When you're at Wallyworld, always cruise the Sporting Goods Counter.  Get to know the guy that runs the Sporting Goods Department.  Check out the displays.  There's usually something "marked down".

Federal PowerShok  5 for $2.77

Win Silver Box  15 for $5.97  

Both are 1 ounce  2  3/4"  shells, but the Wins are a tad taller, with higher brass, sitting side by side on the desk.  The slug in the Federals looks a little cleaner.  I wouldn't want to be hit with either.  Both look like they could disable a computer, VCR, or a dipshit trying to get into your house.

The Wins have higher brass than the Federals.  Federal claims 1610 fps, the Wins state 1600 fps.  Negliable difference...

Wallyworld at Northpoint Winston-Salem has a shitload of the Federals left.  I bought all the Wins.

Everybody needs a few hundred rounds of 12 gauge slugs.

Go get some!