Free money: Spend at least $25 at Best Buy, get $25 cash back (Update: Expired)

This deal is a rerun, but last time out it was for Walmart. Now you have the chance to save $25 at Best Buy.

I've long sung the praises of cash-back services, which can help you save extra on many, if not most, online purchases. This works even if you're already using a cash-back credit card (which you should be). It's like double-dipping, which is just as awesome here as it is at the ice-cream shop.

There are many cash-back services, and one of them, TopCashback, has a fantastic deal for newcomers: $25 cash back when you make a qualified purchase of at least $25 at Best Buy. Once again, this is for new TopCashback members only. If you see a message saying you're not eligible for this deal, it's because you already have an account. 

It works like this: Using the above link or button, sign up for a TopCashback account. It's free and requires little more than your name and email address. From there you'll be taken to the freebie-offer page, where you can click Get Offer. That will take you to the Best Buy home page.

Now just shop like you normally would (but please keep reading so you understand everything that happens next). You could buy, for example, a Microsoft Arc Touch Mouse, currently on sale for $29.99. (Don't buy it via that link -- you have to proceed to Best Buy through TopCashback, as described above. This is just to give you an example.) Once you collect your cash rebate, your net cost drops to just $5. Again, all you have to do is spend at least $25 to get your $25 rebate.

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Another example: The Powerbeats Pro true-wireless earphones. They're $199.99, which is already $50 off the regular price, but the cash-back offer would drop your net cost to $174.99 -- currently the best deal anywhere.

Here's the important thing to note, especially if you're new to cash-back services: When you get to the checkout page, you won't see any evidence whatsoever that TopCashback is doing anything. It records your purchase behind the scenes, much like your cash-back credit card does. Don't freak out: As long as you went to Best Buy's site by way of the TopCashback site, the latter will track your order and award your $25 accordingly.

Speaking of which, it may take up to 24 hours to see the Best Buy purchase recorded in your TopCashback account, and the full $25 amount might not appear for 14 days. At that point, you can get your $25 in the form of direct deposit, PayPal or even a gift card.

Unsurprisingly, there's some fine print, starting with this:

Exclusions: Best Buy Gift Cards, All Desktops, Warranties, Infant Electronics, Infant Toys, Infant Wearables, Apple Watches, Apple Airpods, Apple TV, Apple iPhone Hardware, Apple Desktops, Apple Laptops, Apple Tablets, All Gaming Hardware, Third Party Gift Cards & POSA Cards are not eligible for cash back.

Be sure to read all the details on the offer page, just to avoid any surprises. (If anything crops up, TopCashback has set up a special email address just for this promotion: cnet@topcashback.com.

My advice to cash-back newbies: Buy something you need or want that's in the neighborhood of $25, then settle in and wait for your rebate. If you like the end result (and I suspect you will), keep using TopCashback for other online purchases. One other tip: If you use an ad-blocker, turn it off while shopping. It can get in the way of your purchase getting recorded properly.

You've got until midnight on Feb. 16 to take advantage of this offer. After that, you can still get cash back for stuff you buy at Best Buy -- just not the bonus $25. 

CNET's Cheapskate scours the web for great deals on tech products and much more. For the latest deals and updates, follow the Cheapskate on Facebook and Twitter. Find more great buys on the CNET Deals page and check out our CNET Coupons page for the latest promo codes from Best Buy, Walmart, Amazon and more. Questions about the Cheapskate blog? Find the answers on our FAQ page.