The World Longest Yard Sale is 690 miles long and runs from Addison, Michigan to Gadsden, Alabama. Known as The 127 Corridor Sale, this mammoth  gathering of bargain hunters and sellers is celebrating its 25th anniversary this summer. It runs from August 2-5. Whether you're trying to get a great deal at this epic yard sale-- or the one around the corner-- here are some tips for haggling like a pro at your summer yard sale.

Have a Script Preparedyard sale

Finding the right words when haggling can be the toughest part about scoring a deal. You don't want to offend the seller and you don't want to come off as cheap, so what comes out of your mouth is very important. Financial coach and coupon queen Christine Luken offers up lines to practice. "Ask, 'Is that price firm?' Then be quiet and let them talk. People are usually uncomfortable with silence and will rush to fill it, frequently offering a lower price," she says. And when their response isn't as low as you were hoping? "When they counter your offer say, 'That's not good enough.' Sometimes they'll go lower." And if they don't be ready to walk away.

Bundle and Bid

A sure-fire way to save money at that  yard sale is a tactic Natalie Rojas of Bargains Boutique Store calls "Quarter Bundles." Quite simply, she figures the seller will be more likely to haggle and cut a deal if Natalie is willing to buy more. "I find a few items, add up the prices they are asking for the items. If the price totals $5 I make an offer of $3.75, 25% off," she explains. Sellers are usually willing to reward good customers so if you find two or three items you want, you're likely to get them at a bigger discount.

Know the Item's Value

If you're dealing with typical household goods you may have a better idea of what something is worth. But if you have your eye on an antique or collectible, know its worth before you haggle. Carry your Smartphone and search for similar items on eBay or another online auction house. Or use a resource like WorthPoint, a database that shares the value of over 100 million items based on recent sales figures. Get a free 7-day trial to the service or pay $9.99 a month for a subscription. Find data about what it sold for in the past so you know if it's a good deal now.

Shop Later in the Dayyard sale sign

Sellers may not be as willing to budge on the price at the very beginning of their yard sale. Of course, the selection is best  right when the garage door goes up, but according to professional organizer Rosemary Flannery, deals are better towards the end. "I am almost always willing to negotiate since I always vow that unsold items cannot come back into the house," she says. "As the day goes on and items don't move, sellers are usually more amenable to haggling." But no matter when you ask for a lower price, Rosemary says it's important to be polite and not devalue a person's wares. The good news is you don't have to be a mean haggler to leave the yard sale with a great deal.

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