Prime Big Deal Days (or October Prime Day) starts Oct. 6 and ends on Oct. 7, and as usual, we'll be keeping you updated on all the best deals leading up to and throughout the mega-sale. As you're adding item after item to your cart during the sale, you might be tempted by Amazon's "affordable monthly payment system." Also known as "buy now, pay later" (BNPL), the pitch is a tempting one: Buy what you need now, and pay later, "on your own timeline." But as convenient as it sounds, you should think twice before using buy now, pay later options, whether during Prime Day or at any other time.

While BNPL plans can allow you to pay for purchases in installments without interest, they come with a cost that can easily outweigh any big discounts. Let's take a look at the hidden costs of BNPL, and why you're better off paying upfront for all your Prime Day purchases.

How does Amazon's buy now, pay later program work?

To be clear, Amazon doesn't have its own buy now, pay later program, and the company is not uniquely misleading on this front. The process is straightforward: you choose your items, select Affirm (a third-party lender) at checkout, complete a quick application, and receive an instant decision on your loan terms. Individual transactions initiated through Affirm are limited to $25,000, with a daily maximum of $100,000 across multiple purchases—but of course, your Prime Day splurge will be nowhere near that big, right? (Right?!)

The main draw of these programs is the ability to "pay at your own pace." If you are required to pay a down payment, that is due at the time of the transaction. From there, your first monthly payment is usually due one month after your purchase is processed. Each following payment will be due one month later, on the same day of the month.

You can choose your own timeline, usually spanning 3, 6, 12, or 24 months, depending on the purchase amount and your creditworthiness. Unlike traditional credit cards, Affirm shows you the exact payment amount and total cost upfront, and claims no hidden fees or compound interest.

You need a separate Affirm account in addition to your Amazon Prime membership. The application process requires basic information, including your name, mobile phone number, date of birth, and the last four digits of your Social Security number. Affirm performs a soft credit check initially, which doesn't impact your credit score, though they may conduct a hard inquiry for some loans.

BNPL plans are helpful if you really need to finance something big, but whenever possible, it’s best to avoid taking on debt for everyday expenses.

It makes impulse spending easier

The ease of this sort of financing can make expensive purchases feel more affordable than they actually are. When you can buy a $1,000 tablet for "just $67 per month," it's easy to lose sight of the total cost, as well as your overall financial picture. In turn, this makes it all too easy to overspend on items you might not have purchased otherwise. You're better off taking a breath, stepping away from your shopping cart, and setting alerts to be notified when a product hits a price you can stomach, at a time you can afford it.

It can impact your credit score

Despite what you may have heard in the past, BNPL purchases can now affect your credit score. For Amazon specifically, all Affirm payments (including on-time, late, and missed payments) are now reported to the credit bureau Experian. So if you miss payments or default on the installment plan, it will cause damage to your credit score—making it even harder to get approved for mortgages, auto loans, credit cards, and other financing down the road.

You'll have limited purchase protections

When you use a credit card, you get valuable purchase protections like extended warranty coverage, price protection, and the ability to dispute fraudulent charges. BNPL plans generally don't come with these safeguards. This means you're on the hook if something goes wrong with your Prime Day purchase and the retailer doesn't make things right. The smarter move is to only buy what you can afford during a sale, no matter how tempting those deals may seem.

Although installment plans are helpful if you really need to finance something major, it’s best to avoid taking on debt for everyday expenses. Better to wait for a good price for something you truly need and can afford to pay for right now.

The bottom line

If there's a big-ticket item on sale for Amazon Prime Day but it's still out of your budget, consider these two questions before you turn to BNPL through Affirm:

  • Is this really an essential purchase? BNPL should really only be used on completely necessary purchases that you can’t afford right now, but can afford in six weeks. On that note...

  • Will I be able to pay this off within six weeks? When a bigger payment gets broken down into smaller installments, you might find yourself overspending in the long run, because it "feels" like you can afford it. Stay on top of how much you’re actually spending—especially if you're considering multiple BNPL purchases—and how it will impact your overall budget going forward.

For more information about deals and discounts, keep an eye on all of Lifehacker’s Amazon Prime Day coverage.

Amazon Prime Day FAQs

When is Prime Day in October?

October Prime Day is a two-day event that starts Oct. 6 and ends on Oct. 7.

What goes on sale on Prime Day?

Since Prime Big Deal Days happens in the fall, you're likely to see more deals on gaming and indoor gym equipment. Amazon has already announced some of the 35 categories that will be on sale, including beauty, tech, kitchen, fashion, and home. Some brands Amazon has already mentioned are: Shark, Princess Polly, Soundcore by Anker, UGG, Nest New York, Sony, Tarte, Adidas, and Barefoot Dreams.

Is Prime Day once a year?

Prime Day happens every summer. Prime Big Deal Days (or October Prime Day) happens every October. Big Spring Sale happens every spring.

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