ROCHESTER, N.Y. – Amazon Prime Day, a 48-hour event, started Tuesday at 3:01 a.m. However, it’s not accurate to believe everything on sale is a good deal. Much of what you see that says “on sale” has been listed before at a lower price.

To ensure you’re getting the best deal, take note of these two browser extensions: Camel Camel Camel and Keepa. Both will give you the price history of the product, so you can see if the sale is good.

Amazon won’t disclose how much money it makes during Prime Day, but it gave a hint by calling last year’s event the single largest sales day in the company’s history, selling 375 million items.

Here’s what to expect: As usual, the best deals will be on tech, especially Amazon products. Clothes and school supplies are great as well. Also, consider buying essentials like cleaning supplies. However, do not buy TVs as you’ll find better savings during Black Friday. Toys, gaming consoles, and kitchenware are also things to buy during the winter sales, not now. If you’re in the market for furniture or appliances, the best times are Memorial Day and the Fourth of July.

Lightning Deals are usually deep discounts on items in limited stock. The deal lasts a short time, anywhere from two to six hours. To watch for these deals, visit the upcoming deals section on your desktop or app. Then click “Watch this deal” and you’ll get push notifications on your phone when the deal starts.

Invite-Only Deals usually sell out very quickly. Amazon has created a limited number of deals that are open by invitation only. On the deals page, you’ll see a list of invite-only deals and a button you can click to request an invitation. If you’re chosen, you’ll get a notification and an email to buy the product. You have to buy it before Prime Day ends.

It’s important to note you have to be a prime member to get most of these deals. If you’re not, you can get a trial membership for 30 days and cancel after Prime Day. Some of the best early deals include a golf range finder for 82 percent off and a Ring doorbell camera for 50% off.

But before you get any deal, check to make sure it’s a good deal, and don’t be tempted to overspend.

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