I'm a bit ashamed to admit this, and at the same time hope none of the locals are reading", but I go to Walmart almost every day over lunch. I check the dates of the packers and can pretty much tell when they are getting ready to mark one down. I typically get them around $1.29 a pound and have paid less than a $1 a pound. They are older and/or have a cracked cryo. I know it's shameful, but I'm a cheap cook.
When I'm asked to cook for family and can't play the wallyworld game, I've bought the angus packers from Sams. I will admit that the marbling is more uniform and the point has more edible meat, for the most part there's not a lot of difference.
You have to remember, brisket is one of those things that put BBQ on the map. It's such a poor cut of meat that low and slow is the only thing that can make it edit. Either way the flavor is there, so it really doesn't matter where you bought it. That is, at least for the ordinary farm grown cow. This is of course excluding Wagyu and the like. But as Alton Brown would say, "that's a whole other show".