The first time I walked into a wholesale store, I was blown away by the sheer quantity of items on the shelves. Stacks of 24-pack paper towels and 500-count paper plates lined one aisle. In the food section, you could buy "twin" family-pack jars of ketchup and jelly. Local grocery stores also offer lots of bulk buys. And in most cases, buying in bulk can mean less less cost per unit, less packaging waste, and less trips to the store.

The human brain is wired for hoarding. Back when hunting and gathering meant more than driving to the grocery store, humans knew to "stock up" on food items when they were available because that food might not be available tomorrow.

Fortunately for us, modern grocery stores are restocked daily! Is buying in bulk still the best way to save money, or is it just another gimmick to encourage customers to buy more stuff? Let's find out.

What's the price?

We've been trained to think that bulk buying is cheaper but this isn't always the case. Some companies use this myth to encourage us to buy bigger packages at a higher cost.

Fortunately, there's an easy way to tell if a bulk item is cheaper than the regular-sized product. Check out the "price per unit" on the price tag. Next to the retail price, there is a smaller price breakdown, listing the item's cost per ounce, pound, or unit. Compare this price to smaller and larger packages to find the best price.

Don't be fooled by sales! I've often found that when one size of a product is on "sale," there's still a larger (or smaller) package that costs less per ounce. Comparing prices takes just a few seconds, but can save you hundreds of dollars over the course of a year.

Perishable vs.nonperishable

While our instincts might tell us that bigger is better, consider whether you will use bulk products in a reasonable period of time.

If you've got young children and lots of spills during meal times, it's probably a good idea to buy paper towels in a 24-pack. Will your family struggle to use a bulk product or do you simply not have the storage space? Stick with smaller packages.

If you've got the space and the money to buy in bulk, you can usually save by stocking up on nonperishable goods. Calculating the "cost" and savings of perishable foods can be a bit harder to determine. Think ahead to decide if you'll use a bulk product before it expires or goes bad.

I've got a few cans of diced tomatoes in my pantry right now and I'm regretting buying them. Why? Because I bought 28-ounce cans instead of my normal 8-ounce cans. It made sense at the time: the larger cans were much less expensive, and they'll stay good through 2012.

But I wasn't thinking of our family's typical recipes. We rarely use such a large quantity of tomatoes at one time! Once I open a large can, I'll have just a few days to use all of the tomatoes before they spoil.

While I know that I'll find a way to use these tomatoes (we'll make chili a few times this fall, just to finish them off), it's an important lesson to learn.

Whether you're looking at canned tomatoes, condiments, or any perishable good, remember it's not a "great deal" if you throw half of the product away!

I like to eat yogurt for lunch and snacks, so I usually buy yogurt in 32-ounce containers. But when I'm on the road for most of the week, I never eat the entire container before it spoils so instead of throwing half of the container away, I'll pay a little bit more for individual yogurt cups.

I can open one individual cup and enjoy it, without having to think about when I'll eat the rest. There's always an added cost for convenience, of course. But there's no sense in paying for something that will wind up in the trash.