By sweetening your offer with something that lightens the seller's load, you can score deals.
Stark recommends going to the ATM beforehand, then asking at the store, "Do you have a lower price if I pay in cash? I'm ready to pay now." By offering an immediate sale and saving them from credit card fees that cut into profits, stores may lower the price and waive sales tax.
If it's hard to reduce the stated price, find another way to lower it. "A contractor came to my house recently to give me an estimate for installing windows, and my reply was, 'I'll say yes today if you pay the sales tax.' He jumped at that, and reduced the total cost by $250," Reed says.
If you don't mind floor models, closeout products or flawed items, ask to buy them at a discount. Also, many department stores automatically give 10 percent off -- even 20 percent when asked nicely -- on damaged items.
And the more you buy, the more you should ask for a discount. "You like a TV model so much, you decide to buy two," Cohen says. "You have the right to ask 20 percent off both."
A lower cost on services is even easier to negotiate. Ask for a discount on such things as a half day of spa treatments or multiple car repairs.