Prime Day deals: What’s hot, how does it work; what’s Walmart countering with?

It’s Prime Day on Amazon.com, and if last year is any indication, the  folks at Amazon will likely have a big  smile on their faces.

Last year’s event – which was in honor of the retail website’s 20th birthday  – turned  out to be the  largest global sales day for the company up to that date.

However, the hashtag #primedayfail began trending by the end of the day when deals sold out quickly and customers turned into angry mobs – at least angry online mobs.

Amazon says there is plenty of inventory, but, unlike the Internet, it is limited. (Hint: you should be up and shopping by now).

Not to be outsold, Walmart has launched a “Rollbacks” sale that rivals Prime Day. The world’s largest retailer started its sale on July 1, and has some deals of their  own to offer.

Here’s a quick look at what shoppers need to know:

What is it?

Amazon is offering its Prime customers around the globe more than 100,000 deals – according to the website – in just about every category of shopping it offers.

How does it work?

According to Amazon, there are deals on TVs, electronics, toys,  books, movies  and more. Shoppers will find three types of deals, “Savings and Deals, “Spotlight Deals,” and “Lightning Deals. The company says customers will like Spotlight Deals as you’ll find they are the best of the day. A lightning deal is available for only a few hours. Savings and Deals are good buys throughout the day, the company says.

What do they have on  sale?

Here are a few deals:

When does it start?

The sale began at 3 a.m. ET Tuesday.

Who can shop?

Customers with Prime memberships are the only ones who can take advantage of the deals. But wait, there’s a catch and it’s a good one if you want to be part of the fun: You can sign for a free 30-day Amazon Prime membership. If you just want to shop today’s bargains, you can cancel before the end of the 30-day period to avoid the membership fee.

Where  do I go to start shopping?

Walmart's Rollbacks

What’s Walmart got to do with it?

Not a thing, expect there’s no way the retail giant is letting Amazon have all the fun. Walmart is countering Prime Day with a sale of its own.

What can I expect from Walmart?

Walmart started the sale early – just as Amazon did. It’s “Rollbacks” include price cuts on toys, outdoor and summer items and a few Apple products (Apple iPhone 5S on Straight Talk Prepaid is $149.) The company sweetened the deal on Monday when they announced that shipping on all online orders is free through Friday.

Any other bargains?

Here are a few:

Why are they doing  it?

Because they are Walmart.

Where do I go to find Walmart’s sale?