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MIAMI (CBSMiami) – It’s become known as the Black Friday in July.

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Monday night at 9 p.m. Amazon Prime Day kicks off. What started as a mid-year shopping event on Amazon has quickly become a shopping holiday industry wide. Basically, Amazon created its own shopping holiday, but now other retailers are jumping in and offering their own sales at the same time.

Nerd Wallet’s Courtney Jespersen says Prime Day is historically a great time to buy electronics on Amazon – and of course get discounts on Amazon products like the Echo or Kindle. Amazon is cutting the Echo price by 50 percent and the Echo Dot by 30 percent. A Kindle Paperwhite will $89.99 – savings of $30.

This year Dell is advertising competing deals on electronics.

Shoppers will also be able to save up to 50 percent on select video games, consoles, and accessories, up to 40 percent on PC gaming laptops, desktops, and accessories, and 25 percent off select TCL smart TVs.

Prime Day has also become a great day to buy appliances, but not on Amazon. Best Buy, Lowes and Home Depot are offering 40% off. Major home appliances aren’t really Amazon’s sweet spot so you can get those deals if you look elsewhere.

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Jespersen points out that while Amazon is offering hundreds of thousands of deals, they’re not all what you might expect. Last year, for example, there was mustache wax and a night light for your bathroom.

She also warns that not everything that looks like a deal actually is. Just because the comparison price says you’re saving money doesn’t mean the item actually costs that much anywhere else.

John Simpson, with Consumer Watchdog, said two recent studies found Amazon price comparisons were deceptive.

For instance, Amazon listed a set of sheets for $25 marked down from $56 – a $31 savings. But a check of several price tracking sites shows a peak price of just $26.99.

Other price checks revealed Amazon compared its current price on items to their peak price last year.

While that doesn’t mean it’s a bad deal it is, it is a good reminder on Prime Day, or any other day for that matter, to always comparison shop.

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To check out Amazon Prime for Prime Day (and beyond), you can sign up for a 30-day trial and give it a spin before committing your $100.