A Costco store

Not every item sold at a warehouse club is a good deal. Image source: Costco.

When you spend the money to join a warehouse club like Costco (COST -0.56%), Wal-Mart's (WMT 0.31%) Sam's Club, or BJ's Wholesale Club, it's tempting to buy a ton of stuff to justify the membership cost.

The problem is that many items sold in these stores come in bulk quantities that exceed what you will logically use. Buying a "deal" like that leads to waste, or to have to find ways to consume the item. There are definitely items never to buy at a warehouse club and many that you should only buy under special circumstances.

There are, however, some items that are almost always a good deal at Costco, Sam's Club, and BJ's. These six make that list and can help make your membership worth it.

Liquor bottles on a bar

Liquor prices for house brands tend to be well below those for major names. Image source: Getty Images.

Get your drink on

Not every warehouse club location has a liquor store. The ones that do offer tremendous deals on name brands, but even better prices on high-quality house liquor brands.

These are spirits made for the membership-based shopping clubs by major manufacturers, which sell at prices well below the name brands. You may have to try a few to find your favorites, but the potential savings makes that well worth it.

A doctor fits a female patient for a hearing aid.

Hearing aids usually cost less at warehouse clubs. Image source: Getty Images.

Hearing aids

The same hearing aids that are sold for thousands of dollars at brand-name or local mom-and-pop shops cost much less at Costco, Sam's Club, and BJ's. Again, not every location has a hearing center (and in those that do, its hours may not be the same as the full store's). The ones that do, however, will have trained technicians offering hearing tests and customer fittings.

A man slips a ring on a woman's finger.

Who says romance can't be done on a budget? Image source: Getty Images.

Engagement rings

"Costco is one of the best places to get a smart deal on diamond engagement rings," CreditDonkey's Charles Tran told The Motley Fool in an email interview. "The $55 membership fee can save you thousands on a ring."

It's a case of volume. Costco and Sam's Club (and to a lesser extent BJ's) have more buying power than local jewelry stores and chains. They further extend that by only carrying a narrow line of rings. That will limit your choices, but help keep your cost in check.

A man uses QuickBooks on a tablet.

Accounting software can be found at warehouse clubs or on their websites. Image source: Intuit.

Accounting software

These deals vary during the course of the year and by the chain, but in general, the warehouse clubs offer the lowest prices around for popular business accounting software including Intuit's QuickBooks Online. This is the same software you can subscribe to directly from the manufacturer, but at a better price.

Money gift-wrapped with a bow

Buying a discounted gift card is essentially getting free money. Image source: Getty Images.

Gift cards

In a case where selection will vary seemingly day by day, Costco, Sam's Club, and BJ's often have gift cards at deal prices. This could be something like three $25 cards for a restaurant chain for $60. These deals won't just be for eateries, but sometimes also for stores or even gym memberships.

The Hogwarts Express

The warehouse clubs sometimes have discount tickets for Universal Studios (home of the various Harry Potter attractions). Image source: Universal Studios.

Discounted theme park tickets

Some of the biggest theme parks in the country will sometimes offer better prices through warehouse clubs than they do at their own gates. This can be especially true for some of the major attractions in the Orlando area; the companies who own them assume that once a person has traveled there, they're not going to cancel a visit to the attraction because the tickets cost too much. Of course, look at blackout dates, the rules regarding expiration, and how long you have to use remaining days purchased after you use the first one.