This is Part Three of a three-part series about saving money on groceries. Earlier this week, I explained how you can save hundreds of dollars a year by doing a little legwork. Then, I described how I prepare days before going to the store.

OK. The Millennial Miser has now climbed into his chariot and driven to the grocery store — on Saturday, when paper coupons double in value. He skillfully avoided the shoppers playing shopping cart derby in the parking lot.

But we’re not home free. This is where even the best-laid savings plans can go off the rails. My strategy to avoid this revolves around doing three big things.

1. Don’t buy based on brands

I buy most things based not on brand, but what’s on sale and what I have coupons for. And I come prepared with a written-down list so I don’t get distracted by items I don’t need.

My shopping trip starts in the produce section. (Honestly, we should all be spending a good percentage of our time in the produce section.)

Here, I buy a wide variety of fruits and vegetables based on the time of year and the price. I always buy bananas (they’re cheap and rarely fluctuate in price) but I like many fruits and veggies, so I let the prices dictate what I’ll buy.

Fall: apples. Summer: berries and melons. Other times of the year: whatever’s cheapest.

And isn’t moldy. Seriously people. Inspect those containers.

Then, I move on to the lunch meat section. Again, I vary up my purchases week-to-week based on sale prices, and it keeps my sandwiches from getting repetitive. (Stay tuned for another blog post on the virtue of packing a sandwich for lunch!)

I move my way around the edges of the store, picking up the sale-price meat or seafood I meal-prepped for earlier in the week.

Ever notice how almost every food item in the store has several brands to choose from? By just grabbing whatever you see first, you’re overpaying. Compare prices! Look for the store brand. It’s usually cheaper. But if you have a digital or paper coupon for a name brand, that might be your winner.

For a select few items, The Miser is picky. Take orange juice. Here, I’ve got only three options: Simply Orange, Florida’s Natural, and Tropicana. The Miser cares not for the other brands.

2. Buy sale-price nonperishables in bulk

Then, I make my way through the middle aisles, noting the Buy One, Get One sale on English muffins, how the store-brand can of diced tomatoes is half as much as the name brand, and checking to see if my favorite granola is on sale, which seems to be about once a month.

If something nonperishable is on sale, I buy lots of it. The aforementioned granola doesn’t expire for a few months. Pasta. Canned goods. Paper products and toiletries.

Paper products are where you find the best deals. I love it when the $12 six-pack of Bounty paper towels is half-off, then has a $1 discount if you’ve bought a certain number of mixed-and-matched products, and then I pull out of my pocket a $1 paper coupon that gets doubled. That’s suddenly a six-pack of paper towels that’s 75 percent off.

Above all else, The Miser basks in the joy of free things. Toothbrushes and toothpaste seem to be the most common items to get for free, combining coupons with heavy in-store discounts.

It can take 10 extra minutes to go through these middle aisles looking for things you use that are on sale (or that you have coupons for), but this way, you’re not paying full-price for something when you run out of it three weeks later.

Just like that, you’re done. Whew.

3. Check the math!

The shopping may be over, but the saving is not.

When you get to the checkout lane, watch the computer screen that shows each item’s price! Most of the cashiers are diligent, but sometimes items scan at an incorrect price.

Other times, certain discounts (say, buy 10 mixed-and-matched items, get $5 off) don’t calculate. Always check your receipt on the way out the door, too.

As I said earlier in the week, all of this can add up to significant, fairly consistent savings. The last three weeks, I’ve saved: 18 percent, 23 percent, and 29 percent.