"Can you do better than that?" Sometimes that's all it takes to shave off a few bucks from the price of a DVD player or get a handful of additional basis points added to a CD rate.

Though it's sometimes hard to get over the discomfort of asking for what you want, doing so can pay off in spades. The tactic is commonplace at some retail establishments (think car dealerships and flea markets). But it also works with companies that are struggling with retention (any store in your local shopping mall). Studies cite a good success rate for customers who try to negotiate lower interest rates with credit card companies. (More than half get what they ask for.)

This time of year, "Markdown Mania" can be particularly fruitful for bargain shoppers. Price adjustments are becoming more common with everyone from fashion to furniture retailers. If an item you bought is marked down in a particular period of time, a retailer will often refund the price difference. A recent story in The Washington Post says just 5% to 10% of shoppers take advantage of price adjustments.

To make asking a little easier, follow these tips:

  • Know the store's policy. Most stores will honor a price adjustment two to four weeks from the date of purchase. Others, such as Kmart, will refund the difference within 90 days of purchase. Remember to bring your receipt. And mark your calendar: Most stores allow just one price adjustment per item.

  • Ask if the store will match a competitor's lower price. Sometimes all it takes is a Sunday flyer from the store to get a sweetened deal. Some retailers -- such as Circuit City(NYSE: CC) -- will even award an additional 10% off to customers who spot a better deal elsewhere.

  • Have the competitive offer in hand when you make the phone call. One Fool was offered a $25 renewal bonus from his discount broker, but saw a $50 bonus for new accounts from a competitor. When he mentioned that to the customer service representative, the employee offered him 21 additional basis points over the life of the CD. That turned out to be a $75 bonus.

  • If the price means a lot, be prepared to walk. If you are greeted with stony silence after asking for a discount, either take the offer or prepare to shop around.

  • Consider whether it's worth it to shop around. Comparison shopping and standing in return lines take time.