For Amazon Students only, amazon offers a $10 Amazon Credit for free with the purchase of $50 or more in Amazon Gift Cards. That's the best promotional credit we've seen from Amazon for these gift cards. (We saw a $5 credit with a purchase of $45 or more gift cards in May, although, that deal was only for Amazon Mom and Prime members). Some exclusions apply. Deal ends July 31.
Note: The credit (a promo code) will be sent to the email address associated with the Amazon.com account by August 15 and must be redeemed by August 31.