A woman spraying perfume
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Buy cheap perfume off the street at your own risk. There's nothing more frustrating than purchasing a bottle of your favorite scent only to have the fragrance fade within an hour. By looking out for a few simple clues, a savvy buyer can tell if they're picking up a prettily scented spray bottle full of tap water or an authentic product. And as with all other purchases, follow this perfume shopping mantra: If it seems too good of a deal, it probably is.

Purchase your product from a reputable source. Door-to-door salespeople, parking lot pitchmen and street table sellers usually aren't approved vendors for leading perfume distributors, so hold on to your money. Realize that an authentic product will have a price tag to match. A super-cheap price is a great indicator that you just bought a watered-down perfume.

Ask to test the perfume before you buy it. A reputable vendor will allow you to open and try the product for yourself. If they don't or sell the main product in a different bottle than the sample, it's a fair bet that the sale product is diluted.

Notice how long your sample spritz lasts. A good shot of genuine perfume will last for at least six hours, while a watered-down product will fizzle out within two hours. This is due to the lack of actual oils and quality components that make up a real perfume.

Inspect the bottle for tampering. Perfume bottle tops are often pretty tough to crack open so check to see if it's loose or off in some way. According to Fragrance Choice, packaging should be sealed and grammatically correct; the product should be free of air bubbles that are a tell-tale sign of water.

Look at the color of the product. Genuine perfume is usually rich in color. Watered down products aren't. If the color is uneven or thin, walk away.

Spray the perfume onto paper to test its oil content. Perfumes are composed of lots of essential oils and compounds which should render paper transparent. A couple of drops or spray at close range should leave a bit of an oil stain, while the watered down product won't.