Amex is offering $300 back or 30,000 Amex points at popular mattress startup Casper right now - but it's not for just anyone

• Amex Offers are deals for Amex cardholders - they get you cash back or bonus points on purchases with select retailers. Amex cards from the Platinum Card® from American Express to the Blue Cash Preferred® Card from American Express are eligible.
• One of the many currently available offers is $300 back or 30,000 Amex Membership Rewards points with mattress brand Casper.
• To earn the offer, you need to spend at least $1,500 at Casper.com.
• Not everyone will be eligible for this Amex Offer, as these deals are targeted, and everyone will see different offers in their account.
• This Amex Offer is only available until September 2.

If you're an Amex cardholder and you're contemplating a mattress purchase, now is a great time to check your account and see if you're eligible for Amex's current deal with Casper.

Offer details

Until September 2, eligible Amex cardholders can get $300 back or 30,000 Amex Membership Rewards points when they spend at least $1,500 at Casper.com.

Casper's entry-level mattress starts at $395, but it could be easy to meet the $1,500 minimum for this offer if you opt for the higher-end Wave mattress (starting at $1,345 for a twin) or if you buy a bed frame, bedding, or pillows in addition to a Casper mattress.

Note that those are two separate versions of the offer - as Amex often does with its offers, it's running both cash- and points-based versions of the deal. So you could be targeted for one or the other, or neither.

If you're new to Amex Membership Rewards points, consider that travel website The Points Guy values this loyalty currency at 2 cents per point. That means 30,000 points is equivalent to $600. This valuation is based on your options for using Amex points, and by far the most valuable way to redeem them is to transfer them to partners like ANA and Virgin Atlantic to book travel.

If you see this offer in your Amex account, make sure to read the fine print and note any exclusions or other rules. You need to make the Casper.com purchase by September 2 in order to get the bonus points or cash back.

If you're considering buying a mattress from Casper, check out the following Insider Picks reviews:

• Casper quietly updated its most popular mattress - here's what's new and what sleeping on it feels like
• We compared Casper's foam mattress to its new hybrid mattress to determine which bed you should buy

How Amex Offers work

Amex Offers are targeted, which means that not everyone will see the same deals when they log in to their account. The more Amex cards you have, the better your chance at having a certain offer.

You need to add the offer to your Amex account before you make the purchase in order to get the bonus Amex points or the $300 cash back. Here's how you do that:

1. Log in to your online Amex account.
2. You'll see icons in the top right for each of the cards you hold. Click which one you want to find offers for.
3. Once you're viewing the correct card, scroll down on the main account page. Keep scrolling and click "View All" to see all available offers on that card.
4. When you find one you want to use, click "Add to Card." If you want to confirm that it's been activated, click the
5. "Added to Card" tab.
6. Repeat for each card you have.

Read more: How Amex Offers work to help you save money and collect bonus points

Amex Offers aren't the only reason to consider an Amex credit or charge card, but they're a valuable perk, especially since offers change all the time and you can find deals from brands like Levi's, Starbucks, Adidas, and Best Buy.

If you don't have an Amex card, here are some great ones to consider:

• The Platinum Card® from American Express - It has a $550 annual fee, but more perks than just about any other rewards credit card. Get up to $200 in Uber credits each year, up to $200 in airline incidental fee credits each year, and up to $100 in Saks credits each year. You'll earn 5x points on flights booked directly with the airlines or Amex Travel, and get access to various airport lounges.
• American Express® Gold Card- If you eat out, this card can be a very rewarding option, because it earns 4x points at restaurants. You also get up to $10 each month in the form of statement credits when you make a purchase at GrubHub, Seamless, The Cheesecake Factory, Ruth's Chris Steak House, Boxed, and participating Shake Shacks. There's a $250 annual fee.
• Blue Cash Preferred® Card from American Express - If cash back is more up your alley, the Blue Cash Preferred is a great choice thanks to 6% back at US supermarkets (on up to $6,000 per year, then 1% back) and on select US streaming services, and 3% back on transit and at US gas stations (and 1% on back everything else). There's a $95 annual fee.

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