The Summer Guide to Buying in Bulk

NEW YORK (MainStreet) -- Everyone knows buying in bulk can be a great way to save money, and warehouse club stores such as Costco(COST) and Sam's Club(WMT) have made it the basis of their business model. But it's not always a recipe for success.

Buying a year's supply of paper towels might save you a lot of money in the long run, but you might also run out of room in the closet. Meanwhile, some perishable foods might go bad before you have a chance to eat them all. And since the price of certain products tends to fluctuate with time, a poorly timed bulk buy can be a poor investment if you purchase when it's most expensive.

Not all purchases at warehouse club stores such as Costco are wise purchases. Some should wait for the right time, and some should simply be made elsewhere.

To find out which products you should and shouldn't buy in bulk this summer, we spoke to some shopping experts. Keep reading to learn what they had to say about shopping at Costco and other club retailers to save.

Good bulk buy: Charcoal
Charcoal should last more or less indefinitely, according to charcoal maker Kingsford, so if you see it on sale or available to buy in bulk at a discount, by all means stock up. The one caveat is that charcoal can get very difficult to light if it gets wet, so if you don't have a dry place to store it, we'd recommend getting only one bag at a time.

Good bulk buy: Paperware
If you like to barbecue, chances are you're going to go through a lot of paper plates and cups over the course of the summer. So why buy one package at a time when you can save time and money by buying in bulk?

"Paper goods are really well-priced at the club stores," confirms Teri Gault of The Grocery Game.

Get a stack of paper plates and cups a mile high, and if you don't use them by the time barbecue season comes to an end, stick them in storage for next year.

Good bulk buy: Gardening goods
Prices of different goods fluctuate with the seasons. Take gardening supplies: They tend to spike in price when demand is highest early in the spring, but by the time summer is in full swing you can stock up on the cheap as demand dwindles and stores seek to unload stock.

"I can definitely see garden supplies being a great bargain right now," says Julia Scott, a shopping expert who runs the annual Frugal Festival. "Garden tools and terra cotta pots don't go out of style, even if they're priced like they are."

If you can find a good bulk deal on potting soil or top oil, you should also go for it. Dirt doesn't go bad, as long as you keep it sealed to prevent it from drying out.