#1 - Connolly's - Gloucester, MA (Main St)
#2 - David's - Salisbury, MA (Rt 1 - Bridge St)
#3 - Rownands - Beverly, MA (at the Beverly Salem Bridge)
Conolly's takes only cash and closes at 3PM. Free ice and bags for it. They often carry fresh frozen softshell crabs very cheap!
Davids has a huge selection, including crabs in season, soft-shell and otherwise.
Rowands is a great stop for lobster roll and excellent selection of fresh local fish. The dock is 25 yards from the store.