Christmas in July: Walmart, Amazon Throw Down in Epic Discount Battle Given competing sales from two of the world's biggest retailers, other businesses may be bound for slow traffic this week.

Walmart just crashed Amazon's 20^th birthday party.

Last Week, Amazon announced Prime Day, a massive, Black Friday-like sale to coincide with the company's 20^th anniversary. This Wednesday, new deals for Prime members are slated to appear on the site as often as every ten minutes, Amazon said, across dozens of shopping categories.

But the world's largest retailer is now seeking to amp up its digital presence with an online sale of its own. Beginning this Thursday, the day after Prime Day, Walmart is rolling out "thousands of special deals" and "some special atomic deals," as well as adjusting its free shipping minimum from $50 to $35 -- which is the same rate as Amazon.

As opposed to Amazon's one-day event, Walmart's sale will last for 90 days, according to USA Today.

Related: Wal-Mart Eyes Amazon in Potentially Costly Ecommerce Battle

"We've heard some retailers are charging $100 to get access to a sale," wrote Walmart.com chief Fernando Madeira on the company's blog -- referring to the fact that Prime Day deals will only be available to Prime members, who pay an annual subscription fee of $99. "But the idea of asking customers to pay extra in order to save money just doesn't add up for us."

While the fact that two of the world's biggest retailers are battling to undercut one another's prices may mean a windfall for consumers, one wonders whether other businesses might as well shutter their lights later this week given the inevitable frenzy.

And though Christmas in July sales are not a new concept -- retailers like Target and Best Buy have been holding them for years -- the entry of Amazon and Walmart into the fray is bound to raise the profile of these events, which have thus far existed in the shadow of Black Friday and Cyber Monday.

Related: Amazon's New Prime Day Will Be a Massive 'Global Shopping Event'