Buy Now, Pay Later: What Affirm, Klarna, and Afterpay Actually Cost

You’ve seen it at checkout: “4 interest-free payments of $37.50.” The price on the screen doesn’t change — but it suddenly feels smaller. That’s not an accident. That’s the entire design of Buy Now, Pay Later (BNPL).

Affirm, Klarna, and Afterpay have become fixtures at checkout for everything from sneakers to sofas to plane tickets. Used carefully, they can be genuinely free. Used carelessly, they can quietly reshape your spending in ways that never show up on the price tag.

Here’s what each one actually does, where the real costs hide, and how to decide if BNPL belongs in your personal finances.

The difference between price and cost

Before getting into the specifics, it helps to separate two ideas that get treated as the same thing: price and cost.

Price is the number on the tag. It’s public, fixed, and the same for everyone.

Cost is what a purchase actually takes from you — the impact to your personal finances, and to the future version of you who may still be paying for a decision you barely remember making.

Most of us were taught to read price tags and shop for deals. Almost none of us were taught to measure cost. BNPL sits right in that gap, which is exactly why it’s worth understanding before you tap “Pay in 4” at checkout.

How Afterpay works

Afterpay splits a purchase into four equal payments spread over six weeks, with the first payment due at checkout.

The good:

No interest if you pay on time
Only a soft credit check, so it won’t affect your credit score to use it
Simple, predictable structure — four payments, six weeks, done

The catch:

Late fees of up to $8 per missed payment, capped at 25% of the order
The system is rigid: miss a payment and you’re typically locked out of using Afterpay again until you catch up
No flexibility if your budget shifts mid-cycle

Returns and refunds: If you return an item, Afterpay doesn’t pause your payment schedule automatically — you’re still expected to keep paying on time while the return is processed. Once the merchant approves the refund, Afterpay applies it to your remaining installments first, and any leftover amount is refunded to your original payment method. If you’ve already paid in full before the refund posts, you’ll get the full amount back — but that can take days to show up.

How Klarna works

Klarna offers more variety than Afterpay. Its “Pay in 4” and “Pay in 30” options are both interest-free, while its longer financing plans run anywhere from 6 to 24 months at APRs between 0% and 29.99%.

The good:

Pay in 4 and Pay in 30 are genuinely interest-free if paid as scheduled
Longer financing can make sense for bigger purchases if you qualify for a true 0% promotional rate
More flexibility across short-term and long-term needs than Afterpay

The catch:

Those 0% promotional periods can flip to deferred interest if the balance isn’t paid in full by the end of the term — meaning you could owe interest retroactively on the entire original purchase
Read the fine print on any promotional rate before you commit
Like Afterpay, multiple short-term plans can pile up across different purchases

Returns and refunds: Klarna also expects payments to continue on schedule while a return is being processed — it does not automatically freeze your installments. Once the merchant confirms the return, Klarna typically adjusts your remaining payments or issues a refund to your original payment method, but this can take one to two billing cycles depending on the merchant’s own return timeline. For longer financing plans, any interest already accrued on the returned portion is generally not refunded.

How Affirm works

Affirm focuses on longer-term loans — typically 3, 6, or 12 months — at APRs ranging from 0% to 36%, depending on the merchant and your creditworthiness.

The good:

No late fees, which is a real differentiator from Afterpay and Klarna
Some merchants offer true 0% APR financing
Clear monthly payment structure for larger purchases

The catch:

Affirm reports to the credit bureaus, so a missed payment can affect your credit score — a cost that never appears at checkout
Affirm often advertises “you’ll pay $X total” rather than stating the APR directly, which can obscure just how expensive a 30%+ loan really is
A loan that sounds manageable monthly can still carry a high effective interest rate

Returns and refunds: With Affirm, you’re responsible for continuing scheduled payments until the merchant processes the return and notifies Affirm. Once that happens, Affirm applies the refund to your loan balance — reducing or eliminating remaining payments — and refunds any overpayment to you directly. Importantly, if you’ve already paid interest on the loan before the return is processed, that interest is typically not refunded, even though the loan balance itself is adjusted.

Where the real costs hide

For a single, on-time “Pay in 4” purchase, all three services can be genuinely free — the price and the cost are the same. But that’s rarely where the story ends. Here’s where things tend to go sideways:

You spend more. Research consistently shows BNPL users spend more than they would with a single upfront payment. When a $200 purchase becomes “four payments of $50,” the psychological barrier to buying drops — even though the total cost hasn’t changed.

The plans stack. It’s easy to have three or four BNPL plans running simultaneously across different apps. Each one feels like “no big deal” on its own. Together, they can become a budget category you can’t even see, because no single statement shows the full picture.

Returns get complicated. As outlined above, none of the three pause your payment schedule the moment you initiate a return — refunds typically lag behind the merchant’s own processing time, and any accrued interest is rarely returned. That means you can end up making payments on, or even fronting interest for, something you’ve already sent back.

There’s no safety net. Unlike a credit card, BNPL purchases typically come with no fraud protection, no chargeback rights, and no extended warranty coverage. If something goes wrong with the purchase, you have far less recourse.

Your credit can be affected. With Affirm in particular, missed payments are reported to credit bureaus — a consequence that has nothing to do with the price you saw at checkout.

The bottom line

BNPL isn’t inherently a bad tool. For a disciplined, single, on-time purchase, it can be exactly what it advertises: a free way to spread out a payment. The problem is that it’s designed to make the price feel smaller while the actual cost — to your spending habits, your budget visibility, and potentially your credit — stays hidden until later.

A useful gut check: if you suspect you’d carry a balance anyway, a credit card with a 0% introductory APR is almost always the better deal. It typically comes with fraud protection, purchase protection, and none of the rigid lockout structures that come with services like Afterpay.

Before you tap “Pay in 4”

The most powerful shift isn’t avoiding BNPL altogether — it’s changing the question you ask before using it. Instead of “can I afford this payment?” ask “what will this actually cost me?”

A few ways to put that into practice:

Know your number. Your Impact Number is the most important number in your personal finances and where all wealth building begins. Your Impact Number equals income minus expenses, every 30 days. It’s the money you have left over each month to grow. Maximizing your Impact Number is the first step in the Financial Impact System™, the strategy I used to eliminate $67k of credit card debt in three years.

Once you are in the habit of calculating your Impact Number, you can maximize it. There are two ways to do this: increase income and decrease expenses. My wealth journey began by reducing and eliminating unnecessary expenses. I use Tiller to help me track my spending.

Yours can begin with reducing or eliminating expenses too, or perhaps you want to increase income. There’s no right or wrong way – there’s only “what feels right for you right now.”

Awareness is the seed of transformation.

Once you know where your money is going, I.e. your expenses (all of them over an entire year, averaged monthly) you have the awareness you need to pay yourself first and start building wealth. You’re ready to decide what amount to automatically transfer each month to your savings, retirement, and investment accounts.

Simply subtract your expenses from your net income. That’s your average Impact Number.

Build a spending plan, not just a budget. A plan tells your money where to go on purpose. If you do use BNPL, be sure to add that payment into your spending plan to see how it affects your Impact Number. And remember, the money game is a long one. Be sure to be kind to yourself as you create awareness and take little action steps each day.

Ask the cost question first. Before clicking “Pay in 4,” pause and ask what this purchase will take from you over the next six weeks, six months, or longer — not just whether this week’s payment fits. Also ask, “will this purchase contribute to what I value?”

None of this requires being perfect with money. It just requires reading the other number — the one that doesn’t show up on the price tag.

Want help building a spending plan that keeps decisions like these in your control? Learn more about working with Holly.

Disclaimer: This article is provided for general educational and informational purposes only and does not constitute legal, financial, tax, or credit advice. The terms, fees, interest rates, and policies of Affirm, Klarna, Afterpay, and other Buy Now, Pay Later providers are subject to change and may vary by merchant, individual creditworthiness, and other factors. Always review the current terms and conditions provided directly by the relevant company before making a financial decision. For advice specific to your individual circumstances, please consult a licensed financial advisor, attorney, or credit counselor.