Do you shop at big warehouse clubs like Costco, BJ’s, or Sam’s Club to save money on groceries?  Millions of people roam the warehouse club aisles every day in search of the best deals on everything from diapers to hot dogs, from tires to diamond jewelry.

And while some people will argue that warehouse clubs are a waste or even a scam, I gladly pay my annual Costco membership fee because I know it will pay for itself many times over.  Here are a few warehouse club shopping tips to help you make the most of your next trip to a warehouse club.

Compare unit prices.  No matter where you shop, you should always be using the unit price to determine if you are really getting a good deal.  Manufacturers are sneaky and play with the size of their boxes and cans to make it seem like you are getting more than you really are (don’t even get me started on the way they bag potato chips!) and sometimes the larger package isn’t necessarily the best deal.  The only effective way to compare brands and package sizes is to use the unit price.

Don’t buy in bulk if you won’t use it all.  This is perhaps the most common mistake that warehouse club shoppers make.  They buy an item in bulk because the price can’t be beat.  But it spoils before they have a chance to use it all and they end up throwing a sizable portion away.  Sound familiar?  Do yourself a favor and stay away from the 55 gallon barrel of mayonnaise no matter how cheap it seems.

Split bulk items with a friend.  Of course there are ways to take advantage of the bulk-sized items while eliminating the waste of throwing away the portion you can’t use.  Just recruit a friend to be your shopping buddy and split bulk items down the middle.  If 10 pounds of hamburger patties is too much for either of you to use individually, just split the package in half when you get home and share the cost.  That way you both get to enjoy the price and you only come home with what you need.

Split membership costs.  In addition to splitting the cost of individual items, you can split the cost of the membership fee to save even more money.   A $50 membership fee instantly becomes a $25 fee!

Use coupons.  Warehouse clubs generally don’t accept manufacturer coupons that come in your Sunday newspaper.  But they do periodically issue their own coupons and mail them to members.  It is never a good idea to buy something just because you have a coupon for it, but if you can time your purchases to coincide with the coupon effective dates you can easily save enough money to cover the cost of membership fees.

Avoid impulse purchases.   This really goes for any type of shopping, but I find that warehouse clubs are especially effective in generating impulse purchases.  It’s probably because they continuously rotate stock and if you don’t buy an item the first time you see it you might not get another chance.  Nevertheless, your best bet is to stick to your list and avoid caving in to temptation.