It's a great time to open a Delta Amex card and book a flight - these new offers get you miles plus up to $500 back on Delta purchases

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You can earn up to $500 back on Delta flights, but you only have until August 15 to get these offers.

• Two of Delta's personal credit cards are offering welcome bonuses that can get you money back when you book flights, in addition to bonus miles.
• When you open the Gold Delta SkyMiles® Credit Card from American Express and spend $1,000 in the first three months, you can get 30,000 miles. You can also receive 50% back as a statement credit on purchases made directly with Delta in the first three months, up to $300 back.
• The Platinum Delta SkyMiles® Credit Card from American Express is offering 50,000 miles to new cardholders who spend $3,000 in the first three months. With this offer, you can receive 50% back as a statement credit on purchases made directly with Delta in the first three months, up to $500 back.
• These aren't the highest offers we've ever seen in terms of miles, but the opportunity to earn cash back on Delta flights can help you save on travel such as a last-minute summer trip.
• These offers are only available until August 15, so don't wait.

The best way to earn points, miles, or cash back quickly is to open a rewards credit card that's offering a sign-up bonus. Usually, this requires spending a certain amount on the card in the first three months or 90 days, but in the end you get a nice sum of rewards to put money back in your wallet or to help fund your next trip.

Back in April, Delta's Amex cards were offering their highest-ever public welcome bonuses - new card holders could earn up to 75,000 miles. Now, two new welcomes bonuses are available, and while they're not the highest in terms of miles, they can actually be just as rewarding thanks to the opportunity to earn up to $500 cash back when you book Delta flights.

These offers are only available until August 15, so don't wait long to apply if you're interested.

The Gold Delta SkyMiles card is offering new cardholders 30,000 miles after they spend $1,000 in the first three months. As part of this limited-time offer, cardholders can also receive 50% back in the form of statement credits on Delta purchases made in the first three months, up to $300 back.

Click here to learn more about the Gold Delta SkyMiles Card from our partner The Points Guy.

The higher-end Platinum Delta SkyMiles card is offering new cardholders 50,000 miles after they spend $3,000 in the first three months, and 50% back in the form of statement credits on Delta purchases made in the first three months, up to $500 back.

Click here to learn more about the Platinum Delta SkyMiles Card from our partner The Points Guy.

How much are these welcome bonuses worth?

Travel website The Points Guy values Delta miles at 1.2 cents apiece, so 30,000 SkyMiles from the Gold Delta Amex would be worth $360, and 50,000 miles from the Platinum Delta Amex would be worth $600. But since both the Gold and Platinum Delta cards are also offering cash back for Delta purchases, you can get more value if you max out these welcome offers.

Say you decide to apply for the Gold Delta Amex and you're approved. Meeting the minimum spending requirement will get you at least 31,000 miles (more if you make Delta purchases, since those earn 2x miles). That's at least $372 in value based on the 1.2-cent valuation, and if you booked a Delta flight that costs $600, you'd eventually get $300 back on your purchase, adding up to $672 in value.

Just note that the 50% of Delta purchases up to $300 back that you're reimbursed for won't count toward the $1,000 minimum spending requirement. So for the example above with a $300 rebate for Delta flights, you'd actually need to spend another $300 in the first three months, since you wouldn't earn the bonus miles with only $700 in net out-of-pocket spending.

Other card benefits

The Gold Delta Amex card has a $95 annual fee that's waived the first year, and it doesn't charge foreign transaction fees. Other card features include:

• A first checked bag for free on Delta flights
• 2 miles per dollar on Delta purchases, and 1 mile per dollar on everything else
• 20% in-flight savings on Delta flights
• A reduced fee of $29 per person for entering Delta Sky Club airport lounges when you're traveling on Delta (for you and up to two guests). But if you have the Platinum Card® from American Express, remember that you get free access to Sky Clubs when you're flying Delta.

The Platinum Delta Amex card has a higher annual fee of $195 (not waived the first year), and like the Gold card it doesn't charge foreign transaction fees. It also offers the following benefits:

• A first checked bag for free and priority boarding on Delta flights
• A companion certificate that lets you bring someone along for a domestic, main-cabin round-trip flight, available each year after you renew your card
• Earn Medallion Qualification Miles (MQMs) toward Delta elite status when you hit annual spending requirements on the card. Earn 10,000 MQMs and 10,000 redeemable miles when you spend $25,000 on the card in a calendar year. Earn another 10,000 MQMs and 10,000 redeemable miles when you spend $50,000 on the card in a calendar year.
• 2 miles per dollar on Delta purchases, and 1 mile per dollar on everything else

Bottom Line

These Delta offers mix up the standard welcome bonus of miles in an interesting way, by rewarding you with cash back on your flight purchases. If you have any upcoming travel plans, it could be a great time to apply for the Gold Delta Amex or Platinum Delta Amex, get up to $300 or $500 back on your flight purchase, and earn some miles at the same time.

Just remember that this offer is only available until August 15, so you don't have long to act on it.

Click here to learn more about the Gold Delta SkyMiles Card from our partner The Points Guy.

Click here to learn more about the Platinum Delta SkyMiles Card from our partner The Points Guy.