My One Rule for Amazon Prime Day Shopping Helps Me Save a Lot

Each month, NerdWallet highlights one money move designed to help you feel more confident about your finances. This month focuses on shopping sales with intention. It only takes about 20 minutes, but you’ll want to move fast because October discounts are rolling in.

Amazon’s Prime Big Deal Days bring a Prime Day-style event with a fall theme. Target is running Circle Deal Days at the same time, and Walmart is joining in with “deals and more.”

It pays to shop carefully. A recent NerdWallet survey found that 60% of Americans said they bought something expensive and later regretted it.

Rather than browsing aimlessly, I walk through my home first and make a “needs list.” That way, I approach October Prime Day with more purpose and a better sense of pricing.

My rule is simple: a deal only counts as a “Wallet Win” if I would have bought the item anyway.

I also only add something to my cart if it’s at least 30% below its usual price.

Let’s start in the basement.

Basement and stairwell

My first stop is the furnace room. I open the HVAC flap and pull out a dusty filter that has clearly been there too long. A two-pack of Filtrete 20-by-25-by-1 filters goes onto my Amazon list. At $22.99 at the time of writing, the price may not drop much, but I need them.

We hardly spend any time in our damp, gloomy basement. On the way out, I walk through a spider web, which reminds me that we’re also low on insect killer.

Back upstairs, I pass the crooked smoke detector in the stairwell again. The previous owners fastened it with a loose nail, and it still hangs there. I’m finally planning to replace it with a model that also detects carbon monoxide and install it properly. I also need 9-volt batteries to keep the alarms powered.

With Amazon, Target and Walmart selling nearly everything, these events can be a good way to knock out small home projects for less.

Home maintenance and safety items to watch for:

• HVAC air filters, two-pack.
• Ortho Home Defense Insect Killer with spray wand.
• First Alert battery-operated smoke and carbon monoxide alarm, three-pack.
• Amazon or Walmart brand 9-volt batteries, whichever is cheaper.

Fridge and kitchen

I head into the kitchen and open the refrigerator. After checking the water filter date, I realize I’m still fine because I recently bought an off-brand two-pack.

If yours is due for a replacement, this is a good time to shop. Common advice is to change refrigerator filters every six months, and Prime Day-style sales can bring down the cost of name brands from GE, LG and Whirlpool.

Another thing I need is better food storage containers. I’m tired of cramming spaghetti-stained plastic tubs into an overstuffed cabinet, so a glass set is looking appealing.

A peek in another cabinet also reminds me that our cheap wooden cutting boards are warped. I check Amazon’s best sellers and notice a thick bamboo set from Astercook near the top of the list. It’s priced at $39.99 at the time of writing, though price history tools show a typical price closer to $24, so I save it for later.

Kitchen basics to keep in mind:

• Refrigerator water filter, if you need one.
• Glass food storage containers, including Rubbermaid Brilliance glass containers.
• Astercook Deep Carbonized bamboo cutting board set.

Bathroom sink

Next I go to the primary bathroom, where I immediately spot two worn-out Philips Sonicare toothbrushes with grime packed in between.

I add a three-pack of C2 brush heads to my list and hope to find them for $25 or less. If Gillette Fusion5 razor blade refills are discounted, I’ll stock up there too. The eight-pack is priced at $29.94 on Amazon right now, which feels too high to me.

I’m also running low on toothpaste, floss and sea salt hairspray.

Shampoo, soap, body wash, loofahs and other shower essentials can also be smart buys if the discounts are strong enough.

Bathroom items worth watching:

• Replacement electric toothbrush heads.
• Gillette Fusion5 razor blade refills, eight-pack.
• Toothpaste, floss and hairspray.

That wraps up the bathroom. Now I’m off to my favorite part of the house.

Garage and car

I could load up my list with garage gear, but most of it wouldn’t qualify as a true need for my budget. What I can use, though, is a fresh pair of work gloves for leaf season.

Since we’re trying to keep our cars longer, I add a Fram engine air filter to the cart. I also need more Febreze vent-clip air fresheners, especially for my pickup truck, whose previous owner apparently smoked a lot.

Outdoor and auto ideas to track:

• Work gloves.
• Fram engine air filters and cabin air filters.
• Febreze car air freshener vent clips, four-pack.

I probably won’t buy everything at once. So if I stick to just the smoke alarms, cutting boards, electric toothbrush heads and razor refills, the total comes to about $225 before tax at current prices. Apply my 30% savings rule, and a 20-minute walk-through could save just under $68.

More tips for October sale shopping

October’s sales are the warm-up before Black Friday, giving shoppers a chance to prep the home for fall and get a head start on holiday buying.

Amazon, Target and Walmart are all participating, with discounts likely across home decor, Halloween costumes and pantry staples.

No matter what you buy, aim for at least 30% off to make the purchase worthwhile. A price-tracking browser extension can help you judge whether a deal is really a deal.

And if it sounds like I’m being too strict with my needs list, don’t worry — I’m not unreasonable. If we find the Barbie Dreamhouse for under $185, we’ll buy it for our 6-year-old and save it for Christmas.

My 8-year-old keeps talking about 3D printers, so I’ll be watching for Bambu Lab printer deals too.

Savings over regret

In a previous Prime Big Deal Days sale, I spent $719 on a discounted Sonos soundbar. It was not part of the budget.

That experience taught me something. Now I start with actual needs and let smaller savings add up — a few dollars off shampoo, a few more off snacks, and one year even $10 off my usual arch-support insoles.

Spend 20 minutes checking your home and look for real savings without regret.

If you’re taking part in this monthly money challenge, begin with the tips above. Next month, we’ll look at how to give holiday gifts for less. If you missed the previous edition, you can revisit ways to lower your utility bill.