Shopping at Costco is pretty cheap, at least when you consider unit pricing. But over at Helium.com, writer Suzanne Rose has come up with a handful of things to think about before clearing out the back of your minivan in preparation for a trip to the warehouse store.

1. You may buy more than you want and some will go to waste:
Generally speaking the best unit price deals at places like Costco come when you’re buying in bulk. But Rose points out that you could be throwing good money away if you’ll never use the entire carton/crate/pallet. “This will be especially true if the item is perishable and you literally end up throwing it out because it goes bad or goes beyond its expiration date,” she writes. “Even if you still use it but do not enjoy it as much because it is not as fresh, then that can be a problem.”

2. They are not cheaper on everything:
“Although Costco is cheaper than other stores in many different things, they are not cheaper in everything,” writes Rose. If you’re truly after says, she says, you’ll have to do some comparison shopping, both with other bricks-and-mortar stores and with online outlets.

3. They do not accept a lot of coupons:
Explains Rose, “Costco accepts their own coupons but not much more.” She says that you can sometimes save more cash by shopping at a store that accepts more coupons, so keep that in mind before you head out to Costco.

Why Costco doesn’t always save you money [Helium.com]

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