This year, deals include $50 off Amazon's Echo smart speaker on sale at $130, half off toys including Nerf and Barbie brands and up to 60 percent off athletic shoes.

Walmart is offering free shipping on all orders from Monday through July 15 and launched new online deals on items including an HDTV and Apple TV. Amazon has a special deal going right now for Prime subscribers only, and the gist of it is this: Amazon will give you a $10 Amazon credit for free when you purchase $50 worth of gift cards and use a special promo code at checkout.

Amazon's "Prime Day" has returned for a second year with the online retail giant promising twice as many deals as last year.

Amazon's monster Prime Day event is packed full of bargains on all sorts of different products, but there's also something else Amazon is offering its customers today: Money. A few hours later, company spokeswoman Ana Rigby said in an e-mail that the issue involving Lightning Deals had been resolved.

Keep in mind, also, that many of Amazon's competitors, including Walmart and Best Buy, will offer deals on Prime Day as well, in an effort to keep up with the sales. It is exclusively for members of the company's Amazon Prime loyalty program. And if you're looking for deals that are guaranteed to be the best around, this is the post for you.

"Obviously "Black Friday" means discount to people", so it's a good workaround, he said.

The one-day sale, for members of its $99 per year Prime subscription service, had been expected to generate up to $1 billion in sales, more than double the amount during last year's inaugural Prime Day sale, according to Citi analysts.

Amazon's Twitter account said it was working to resolve difficulties customers were having checking out.