Thanks once again to Frequent Commenter Bob for his tip to yet another interesting WSJ column, this time about the Costco Effect: when buying at warehouse stores entices shoppers to purchase more than they need.

Sure, you can get paper products and other shelf-stable staples for less at a warehouse store, but if you can't leave the store without picking up a discounted New York Times bestseller or some gourmet snack, you may be frittering away your money.

And if buying your household staples in larger quantities prompts you to use or eat them in greater quantities than you normally would ... are you really saving in the long run? And if you still have to hit a traditional supermarket to get the last few items on your list ... you're vulnerable to even more impulse purchases.

Last Thursday we tipped you off to a Sam's Club membership deal --- just $10 for 10 weeks.  However ...