Amazon offers the Optimum Nutrition Gold Standard Pre-Workout 30 Servings Tub in Fruit Punch for $15. Order via Subscribe & Save to cut it to $14.25 and bag free shipping. That's $5 under our January mention and the lowest total price we could find now by $11. It includes 175mg of caffeine per serving.
Be sure to cancel Subscribe & Save once your order ships or you'll be billed for subsequent shipments.