I was looking to spend the $2 credit from the last sample purchase and saw this as the cheapest option:
20% clipped coupon on the product page, 5% subscribe & save brings it to $16.38
$2.00 credit from last frontpage deal makes it really slick.
Another $2.18 discount if you have 5 subscriptions.
The next cheapest flavors for a 12-pack of Quest bars:
Cookies & Cream $16.81 https://smile.amazon.com/dp/B00I0DI0Z6/
Double Chocolate $16.89 https://smile.amazon.com/dp/B00FEKGO1A/