Subscribe & Save and Amazon Prime required for the best deal. Clip the 30% off coupon to get the best price. This will stack with the Prime 20% discount for a total of 50% off.
$6.60 for a 12-pack comes out to $0.55 per pack, which is really cheap.
Cherry, Strawberry, Black Bean, Spinach and Oat flavor is slightly more expensive at $7.33 after discounts, but is another option if you prefer that flavor. Note that you can only use the coupon once per account.
As usual, remember to cancel your subscription after you receive your first order.