I just picked up some choice beef ribs at Costco yesterday for $4.75/lb. I'm never quite sure if they are plate or chuck. There are 4 bones which used to mean chuck, but I see now plate ribs being cut from ribs 5-8, so who knows. Either way, they are always great.
I also picked up a 12lb pack of choice flank steak. They had a bunch of bags that were mis-labelled as back ribs, for $2.79/lb