Editor’s note: This post has been updated with the latest information.

One of the easiest ways to make the most of your online purchases is by leveraging online shopping portals. Some of these sites even offer one-time bonuses for new members and allow you to refer your friends and family members for additional rewards as an existing customer.

And one of TPG’s favorite portals just launched an increase offer for a limited time.

If you join Rakuten today and spend at least $40 within 90 days, you’ll take home a one-time bonus of $40.

If you’re an existing Rakuten member, you can also get in on the action. All you have to do is refer a friend; when your friend joins and spends $40 within 90 days, you both get a $40 bonus.

If inflation is taking a larger bite of your budget these days, this is a great way to lessen the impact of higher prices. Or, you could even opt for American Express Membership Rewards Points instead as you look ahead to your next trip.

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Typically, Rakuten offers $25 for each referral with no limit to how much you can earn, as long as the new member meets the spending requirements, though the most recent offer was $30. However, if you join without a referral, you’re typically limited to a one-time bonus of just $10.

This is a nice way to get a higher bonus — and to help your friends and family members get in on the action.

Read more: How to earn bonus cash back or Amex points on your online shopping purchases with Rakuten

Overview of Rakuten

In case you’re not familiar with the site, Rakuten is an online shopping portal that used to go under the name Ebates. It partners with hundreds of online retailers, from household brand names like Target and Nike to smaller merchants like Glossybox. By starting your purchase at Rakuten and clicking through to the merchant from there, you’ll take home a bonus on every eligible purchase you make — in addition to earnings on the credit card you use for the purchase.

To make things even easier, you can download the Rakuten plug-in and go directly to the merchant’s site. The browser extension will then notify you if there’s a rebate available:

This friendly reminder makes it simpler to earn more rewards for your online shopping.

Related: Don’t want to miss out on earning bonus points? There’s an extension for that

You may be wondering how this is possible. Rakuten inks marketing agreements with individual retailers, which then pay the site commissions on purchases that begin there. In turn, Rakuten then passes a portion of those commissions on to the customer. The retailer gets additional business, and both you and Rakuten enjoy a cut of those purchases — a win-win-win for all parties.

While Rakuten is advertised as a cash-back portal, you can take your rewards to the next level by switching your earning preference to American Express Membership Rewards points. In the above example, that means you’d take home 1 Amex point for every dollar you spend at Target. Since we value Amex points at 2 cents apiece, thanks to the array of valuable redemption options, that could offer an even higher return for your online purchases. If you choose to earn Membership Rewards points, TPG values the 4,000-point new customer bonus at $80.

Note that going through Rakuten for your online purchases may mean that you’re sacrificing higher rewards through an airline shopping portal — especially if there are any bonus offers through those sites. However, given the current referral offer now available, Rakuten could be a good option.

Not a member? Join Rakuten today to earn a $40 bonus.

Which credit card should I use?

If you’re making purchases online, be sure to pay close attention to any potential bonus categories. However, your best bet may be to use a card that offers solid value for everyday purchases, including the following:

• Capital One Venture Rewards Credit Card: 2 miles per dollar spent on purchases, worth 2 cents when used for travel or 3.7 cents if you use the program’s transfer partners (based on TPG valuations; not provided by the issuer).
• Capital One Venture X Rewards Credit Card: 2 miles per dollar spent on purchases, worth 2 cents when used for travel or 3.7 cents if you use the program’s transfer partners (based on TPG valuations; not provided by the issuer).
• Citi® Double Cash Card: 2% cash back on all purchases (1% when you buy; 1% when you pay your bill) — with the option to combine your rewards with ThankYou Rewards-earning cards for
• The Blue Business® Plus Credit Card from American Express: 2 Membership Rewards points per dollar spent on the first $50,000 in purchases each calendar year; then 1 point per dollar (meaning a 4% return based on TPG valuations). Terms apply.
• Chase Freedom Unlimited: 1.5% cash back that can be transferred to a Chase Ultimate Rewards-earning card for a 3% return based on TPG valuations.

Remember that any cash back or Amex points you’d take home through Rakuten come in addition to the earnings on your credit card. You may even be able to stack an Amex Offer or Chase Offer at select merchants, so be sure to check those now to avoid leaving money on the table.

For example, Saks Fifth Avenue is currently offering 1% cash back (or 1 Membership Rewards point) for every dollar you spend by purchasing through Rakuten.

Holders of The Platinum Card® from American Express enjoy up to $100 in statement credits at Saks every calendar year ($50 from January through June and another $50 from July through December — enrollment is required). Since Amex applies these credits on the back end — as opposed to via a promo code at the time of purchase — you should still earn the cash back or bonus Amex points on the full subtotal of your purchase by starting at Rakuten and clicking through to Saks.

Read more: 10 gifts you can buy using your Amex Platinum $50 Saks Fifth Avenue credit

This new customer offer is a simple one that anyone can utilize, so don’t miss out on an easy $40 or 4,000 points for online shopping. Sign-up for Rakuten today, or begin referring your friends and family members to reap the rewards of their online purchases.

Further reading

• How to maximize online shopping portals.
• The most generous airline and hotel dining rewards programs.
• Best cash-back cards.

Additional reporting by Benji Stawski.