The deal was spotted by one of your fellow readers, Adam.
The $4 Meals feature a choice from a limited selection of entrees plus a medium order of fries and a medium drink.
The entree choices include: 2 Cheeseburgers, a Double Cheeseburger, and a McChicken or Spicy McChicken.
While prices vary, going by my local McDonald's, the 2 Cheeseburgers and Double Cheeseburger represent the best deal as they run about $2, while the McChicken or Spicy McChicken is about $1.39. Medium fries go for $1.79, while any size drink is $1 due to a longstanding promotion (but probably somewhere around $1.50 to $1.75 at regular menu prices). That comes out to about $4.38 to $4.79 for the same items purchase separately (pricing and savings may vary).
Since the Dollar Menu is now the Dollar Menu & More, it's not hard to envision the day where it becomes just the "Extra Value Menu" or maybe the "$2 Dollar Menu." Maybe $4 is the new value sweet spot for McDonald's.
Photo by Adam.