Amazon offers the Folgers Classic Roast 3-oz. Instant Coffee for $2.36. Order via Subscribe & Save to cut the price to $2.24 and bag free shipping. (Walmart offers it for about the same in-store.) That's the lowest price we could find by $2. It makes up to 45 6-oz. servings.
Be sure to cancel your subscription after your order arrives to avoid being charged for subsequent shipments.
Update: It's out of stock at Amazon; however, Walmart still offers it for $2.36 with in-store pickup.