Joining a warehouse club. Warehouse clubs aren't just about 5-gallon jars of pickle relish. They also have great deals on grocery staples such as eggs, butter, milk, cereal and cheese. (Clubs limit their margins to between 11% and 14%, compared with 25% to 30% at supermarkets and mass merchants.) Plus, the savings on big-ticket items like furniture and electronics can more than pay for the annual membership fee of $40 to $50. But use your membership wisely: Only buy what you will use. If you throw away half the food because it expired before you could eat it, you wasted your money.

Buying renter's insurance for your apartment. A renter's insurance policy can be worth the $150 to $250 a year (that's only $12 to $21 a month). Without it, you'd have to pay to replace everything you own in case of a fire, theft or other disaster. You may not think you own much of value, but add up your clothes, furniture, computer, entertainment system, books, movies, microwave, etc., and you could be out thousands of dollars.

Save Your Money

Changing your car's oil every 3,000 miles. Check your owner's manual. Three months or 3,000 miles is the oft-spouted guideline, but in reality, manufacturers typically suggest an oil change every 5,000 to 7,500 miles. Cutting two unnecessary oil changes per year could save you between $50 and $80. And you won't waste time sitting at the car shop.

Taking the brand-name prescription drug instead of the generic. There's generally no difference in quality or effectiveness between brand-name drugs and their generic counterparts, yet the generics cost significantly less.

Investing in a mutual fund with a sales load instead of a no-load fund. Selecting no-load funds can save you more than 5% in sales charges. No matter how well a fund has done in the past, you can't be sure how it will perform in the future. But if you pay a load, you've guaranteed that you've begun the performance derby in the hole to the tune of the load.

Buying an extended warranty for your car. Usually, an extended warranty isn't worth the price. You can typically wait until just before your regular warranty expires before buying an extended warranty. If you've been having trouble with your car, you'll know by then if you need more protection.

Getting accidental death insurance. Your money would be better spent on a life insurance policy. Accidental death insurance pays only if you die in an accident -- which only about 5% of people do. A life insurance policy, however, pays regardless of the cause of death.

Buying premium gasoline when your owner's manual says regular is fine. If your owner's manual doesn't recommend premium, you're wasting your money if you use it. In fact, because it's harder to ignite, the higher-octane gas could make your car harder to start and cause it to run less smoothly, especially in cold weather.