Check out Amazon's running list of Prime Day deals leading up to July 15 and 16 here.

Amazon's members-only summer anniversary sale, Prime Day, is just about the biggest online shopping event of the year after Black Friday. This year, the 48-hour sale will last from 2:59 a.m. Eastern Time on Monday morning, July 15 (midnight Pacific) and run through Tuesday, July 16. In previous years, the sale has only lasted 36 hours, so you'll get some extra shopping time this year.

Outside the U.S.? No problem. Prime Day deals are available in 18 different countries, including the UK, Canada, India, Germany, France, Australia, and more.

Limited-time flash sales can be stressful, and you want to be prepared to grab those amazing deals before they're gone, so here are five ways to prepare to have the best Prime Day yet.

1. Sign up for Prime (obviously).

As the name suggests, Prime Day deals are only for Amazon Prime members. If you don't have a membership yet, sign up for a free trial now—the promotional period lasts 30 days. After that, Prime costs $13 a month or $119 a year. If you're considering whether or not to make the jump to a full Prime membership, check out our list of all the perks Prime gets you beyond just free 2-day shipping.

2. Start thinking about what you want to buy on Prime Day.

Amazon devices are certain to go on sale, so Prime Day would probably be a great time to grab a Kindle e-reader, Fire tablet, Ring doorbell, Fire TV Stick or Cube, or an Echo. Bookmark this page to see all the Amazon device deals next week. What kind of discounts should you expect? Last year, Kindle Paperwhites were discounted $40 for Prime Day (going for $80), while Fire HD 10 tablets were listed for $100, a $50 discount. Prime Day is also often a good day for books: Last year, Amazon offered customers credits toward a future book purchase when they bought Amazon Charts books or Kindle e-books, as well as discounts on Kindle Unlimited subscriptions.

Other things that have gone on sale in previous years: Instant Pots, 4K TVs, luggage sets, Blu-rays, smartphones, FitBits, robot vacuums, and more. There's a higher likelihood that last year's models will go on sale rather than the latest and greatest gadgets, so if there's anything you coveted for Black Friday in 2018 that you didn't end up buying, Prime Day might be your lucky day.

3. Choose the right products—and prepare to comparison shop.

Trying to to decide what to buy? Check out our guide to fake reviews to learn how to spot the real deal, and consider downloading browser extensions like Fake Spot and Honey to help you analyze the quality of reviews and past prices to make sure that what you're buying is actually the killer deal it appears to be. Otherwise, you may discover too late that the massive "discount" you're getting is the same price the item has been listed at for months.

Prime Day has become a big enough event in the shopping world that other retailers have started offering competing deals, too. Macy's is running Black Friday in July deals until July 14 (use the code JULY for up to 25 percent off). Walmart is hosting Google Week, which includes up to 50 percent off products like Google Home and Nest from July 8 to July 16. You'll also want to check out Target's Deal Days on July 15 and 16 (and beforehand, because some things are already on sale), which will include discounts of 30 to 50 percent on small appliances, cookware, furniture, rugs, and more.

4. Check out the pre-sale deals you can already get.

Amazon is already offering a bunch of Prime-only deals in the lead up to Prime Day next week, including discounted Audible subscriptions ($120 per year, with an Echo Dot thrown in for just $1), discounted Marvel movie rentals ($2 each), 25 percent off Pepsi-owned brands like Lay's and Gatorade, and more.

You can already save on products sold by Woot, like this Wi-Fi-enabled countertop garden kit ($140 off right now), Stone and Beam home goods (including cookware sets, furniture, and decor for up to 20 percent off), and various Amazon-branded household goods, like coffee pods, toilet paper, trash bags, pain relief medication, and laundry essentials (all 20 to 25 percent off).

5. Check back with us next week.

Don't forget to return to Mental Floss on July 15 and 16, when the Smart Shopping team will be rounding up the best Prime Day deals as they become available.