In case it wasn’t already perfectly obvious that Walmart is gunning for Amazon, the Bentonville, Ark. giant just kicked up its e-tailing competition.

Walmart announced today that it will also offer thousands of discounts for online purchases on July 15, the same day Amazon plans on hosting its Prime Day shopping extravaganza. And in its blog post announcing the sales, Walmart took a clear swipe at Amazon’s push to have shoppers subscribe to its $99 a year Prime service.

“We’ve heard some retailers are charging $100 to get access to a sale,” the Walmart blog says. “But the idea of asking customers to pay extra in order to save money just doesn’t add up for us. We’re standing up for our customers and everyone else who sees no rhyme or reason for paying a premium to save.”

Related: Amazon’s Prime Concern—A New Online Blitz by Walmart

Walmart, the world’s largest retailer, is also offering another limited-time deal to boost e-commerce sales. Starting today, customers will receive free standard shipping with online purchases that cost a minimum of $35, instead of the usual $50. The change will be effective for at least 30 days. 

In February, Walmart CEO Doug McMillon told analysts on an earnings conference call that the company would invest between $1.2 billion and $1.5 billion in e-commerce throughout the year.

Neither Walmart nor Amazon has released information about specific sale offers yet, so the early hype might prove unwarranted, but the battle is clearly on and now the claws are out.

Update: Amazon responded to Walmart’s gibe with its own accusation. “We’ve heard some retailers are charging higher prices for items in their physical stores than they do for the same items online,” Greg Greeley, vice president of Amazon Prime, wrote in an email to Bloomberg. “The idea of charging your in-store customers more than your online customers doesn’t add up for us.”