When Amazon Prime Members choose FREE no-rush shipping at checkout (vs FREE 2-day shipping), they will receive a $5.99 Prime Pantry Credit.
Keep in mind that the delivery fee for each Prime Pantry box is $5.99 so this credit essentially gives you free delivery! Just head here, fill up your Prime Pantry box with items you want to purchase, and Amazon will automatically apply the credit at checkout.
This offer is good through 5/31/15.
Curious about Prime Pantry? Here is an article about How Does Amazon Prime Pantry Work.
Pricing was current when the post was published, however Amazon prices change often, so please check before you buy.