Amazon has NOW Foods Certified Organic Wheat Grass Juice Powder (4oz)  for $14.20 shipped.  Choose Subscribe and Save to receive 5% off and free shipping.  This brings the price to $0.51/serving (2 level teaspoons).

• This product is vegan and certified organic.
• Wheat Grass Juice Powder is high in chlorophyll, vitamins, minerals, and natural enzymes.
• This green superfood contains no additives, carriers, or insoluble fiber.  Because of this purity, it is easily soluble in water.

Grab this Amazon deal here.

Subscribe & Save sets you up with an automatic shipment plan, but you can cancel if you wish under “Your Account” and “Manage Subscribe & Save Items.” Be sure to verify the price before ordering.