One of the best things I’ve done in a long time is to invite my readers to send in their requests for my Best Inexpensive picks. I’m not sure why I love it so much, but it may have something to do with satisfying my inner shopper without actually shopping.

At any rate, today I’m excited to reveal my Best Inexpensive pick for four completely unrelated but frequently requested items, with links available at http://www.everydaycheapskate.com/bietf.

ELECTRIC TOOTHBRUSH. I’ve gone to the same dentist for so many years that I’m sure he’d be embarrassed if I told you here. Know how much I trust and depend on Richard Oliver, D.D.S., of La Palma, California? I now live 1,100 miles away, but he’s still my dentist, and I still show up for regular cleaning and checkups. Dr. Oliver believes so strongly in the effectiveness of a good electric toothbrush that he gives his patients a new brush head for their particular model every visit. My pick for the Best Inexpensive electric toothbrush is the Oral-B Pro 1000.

Here’s why: It has a built-in timer, so I know how long I have to keep going at it. It gives me an alert when I’m done — and also a pulse every 30 seconds, indicating when I should switch areas. The replacement toothbrush heads are very inexpensive — or free, if you know Dr. Oliver. This brush holds a charge for many days, which makes it ideal for travel. The manufacturer claims that the Pro 1000 removes 300 percent more plaque than a regular toothbrush, something I cannot prove but, having used both, I believe. And here’s the best part: It costs about $40.

FOLDING KNIFE. Having all sons and one husband, I know how much many men enjoy and depend on a decent pocketknife. In my family, I’ve joined those ranks. I love having a good, dependable cutting tool in my handbag. And I know the heartache of losing my favorite well-used and always-sharp knife. That’s when it’s good to know I carry the best that is also inexpensive. My pick for Best Inexpensive pocketknife: Columbia River Knife and Tool’s Drifter G10 plain-edge folding knife.

Here’s why: It is the perfect size and shape. Once folded, it locks in place for safety. The razor-sharp blade is high-quality stainless steel. For the money, this is a super bargain. It’s about $23.

SMART SPEAKER. It started with Apple’s Siri — a voice-activated intelligent cellphone feature willing and able to answer just about any question. Then, about two years ago, Amazon.com introduced its version for the home, featuring the intelligence of Alexa. Don’t know what I’m even talking about? Ask any 10-year-old (or, in my case, any 2-year-old grandson who has fallen in love with Alexa). My pick for Best Inexpensive smart speaker: the Eufy Genie smart speaker with Amazon’s Alexa.

Here’s why: I have been testing Eufy Genie for weeks now and find it to be on a par with Amazon’s Echo Dot in every way. And it’s so much less expensive. It’s about $35.

EXTREME HAND AND BODY CREAM. If you suffer with what one reader describes as “alligator skin,” you’ve most likely spent a fortune trying every possible moisturizing hand and body cream out there. So have I, especially now that I live in a very dry climate. And all of my tests and trials have paid off, because they led me to Atrac-Tain superior moisturizing cream.

Here’s why: This cream is the undisputed best option for every skin type, even extremely dry, cracked skin. Atrac-Tain is miraculous. It is fragrance-free, thick and creamy and goes on nearly dry, leaving no greasy or sticky feeling. This is a miracle in a tube and worth every penny. It’s about $11.

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“I don’t do math. Numbers give me a rash.” That’s a line I’ve used a lot, mostly because it’s true but also because it gets me a laugh.

Truth be told, most of us stink when it comes to doing math on the fly. That’s a problem because being hopeless with math makes us putty in the hands of retailers.

Why is it socially acceptable to say that we’re bad at math but not to say we’re bad at reading? The truth is that it’s not OK to be hopeless with numbers. Here are three ways that our aversion to math costs us money:

THE NUMBER 9. Amazingly, 65 percent of all retail prices end in the number 9. Subconsciously, we’re charmed into believing the item is a bargain.

Whenever you see a product priced at $29.99 or $9.99, the retailer is attempting to charm your brain by marking prices just below a round number. Because our brains are trained to read from left to right, the first digit is the one that sticks in our head and the one we use to decide if the price is right.

Both Steve Jobs, who came up with the 99-cent mobile app, and the guy in California who founded the 99 Cents Only Stores have made millions off this human quirk. Retailers use the number 9 to lure us into buying something because they know we’ll assume it’s been discounted.

This phenomenon is known as the “left-digit effect,” and studies have shown that it absolutely works and has a big impact on our buying decisions. So whenever you see a price ending with 99, get in the habit of rounding up and then deciding whether it’s a good deal.

The good news is that simply being aware of the ways retailers use the number 9 can break their spell over us. Whenever you see a price ending with a 9, stop and think about what’s going on.

INTENTIONAL CONFUSION. It’s a trick retailers use all the time: A confused customer is more likely to opt for the higher price. An item marked “5 for $4” prompts us to buy five items for $4 instead of one item for 80 cents, because it’s too confusing.

Which is the better deal: Thirty-three percent off the regular price, or 33 percent more product for the same price? Studies show that most people go for the deal with 33 percent more because they don’t know how to do the math and they simply guess. And they’re wrong.

Thirty-three percent off is the same as a 50-percent increase in the quantity. Let me show you: If the regular price is $1 for 3 pounds, 33 percent off means you get 3 pounds for 66 cents, or 22 cents per pound. If you opt for 33 percent more, you’ll get 4 pounds for $1, or 25 cents per pound. The secret is to figure out the price per unit — per ounce, per quart, per pound. Then, it’s easy to compare.

PRICE IGNORANCE. In his book “Priceless: The Myth of Fair Value and How to Take Advantage of It,” author William Poundstone tells the story of the retailer Williams-Sonoma and a $279 bread-maker. Sales were lagging, so the retailer placed a nearly identical machine next to the $279 bread-maker with a price tag of $429. Immediately, sales doubled on the $279 model because it appeared to be 40 percent cheaper and, therefore, a great deal. The same tactic is in play when you see a big display in the supermarket with a sign that reads “Special!” If you are not up on your prices, you’ll fall for every trick retailers have up their sleeves to get us to spend more money.

Getting good with math, I’m discovering, starts with my attitude. That’s why I am never again going to tell myself or anyone else that I’m bad with math. I’m doing brain calisthenics. And while forcing myself to figure out price per unit on the fly is a good exercise, I’m also learning that a pocket calculator is my friend.

EDITOR’S NOTE: Mary Hunt is the founder of www.DebtProofLiving. com and author of 18 books, including her latest, “Can I Pay My Credit Card Bill With a Credit Card?” You can email her at mary@everydaycheapskate. com.