Among the bargains are a 50 percent markdown on the Amazon Echo, $50 off the August Smart Lock, and 30 percent off select Under Armour apparel.
And with all the buzz, rival retailers are not about to sit on the sidelines. Instead, they are hoping to capitalize on the heavier-than-normal shopping traffic online this week, too.
"We are seeing other big box retailers use Prime Day as an opportunity to capture shoppers' appetite for deals and as way to compete against Amazon for share of wallet and mindset," PwC's Consumer Markets lead Steve Barr told CNBC.
"But the only way they will draw attention away from Amazon is through great deals," Barr said. "July is becoming equivalent to November with month-long discounts to entice shoppers."
This year, Amazon extended the length of its event to 30 hours, with new deals being featured on Amazon.com as often as every five minutes, the company said. Deals will be organized by so-called most-shopped-for themes. Additionally, Prime members can download Amazon's app to learn about deals up to 24 hours before they go live.
A survey shows 76 percent of Prime Day shoppers visit other major online stores to research product ratings and reviews before making a purchase on Amazon, according to consumer research firm Bazaarvoice.
The top places shoppers will search include Wal-Mart, which draws the most clicks; consumer electronics websites — such as Best Buy — in second place; Target, in third; and home improvement websites — those of Home Depot and Lowe's — also proving to be popular outlets, Bazaarvoice found.
"As one of the biggest online shopping days of the year, many consumers discover and try new brands on Amazon Prime Day," Sara Spivey, Bazaarvoice's chief marketing officer, said in a statement.
"But participation in Prime Day is not the only way for brands to get in front of online shoppers. ... [C]onsumers are researching and buying products across multiple online retailers on Prime Day and the availability of ratings and reviews across these retail channels can help inform and influence their purchase decisions."
Target said it is featuring back-to-school bargains at its stores and online during the week of July 9. This includes "season-long low prices" on school supplies and apparel, a Target spokeswoman told CNBC.
"As always, Target guests that have a REDcard will also receive free shipping on most Target.com orders and 5% off all purchases throughout the year," the spokeswoman added.
Dell is another retailer deciding to roll out its so-called Black Friday in July the week of Amazon's Prime Day. Discounts on Dell's XPS Tower Desktop and Inspiron Desktop, for example, come ahead of back-to-school shopping season, when many students are searching for new computers.
Wal-Mart, which has rolled out deals on past Prime Days, hasn't announced plans to do so this year.
In 2016, Wal-Mart offered a free 30-day trial for ShippingPass, its competitor at the time to Amazon Prime. Wal-Mart has since shuttered its ShippingPass program, replacing it with a promise that shoppers will receive free two-day shipping as long as they spend at least $35 online.
Representatives from Home Depot and Lowe's said they did not have any deals to announce related to Prime Day. Wal-Mart did not immediately respond to CNBC's request for comment.
Other examples of rival retailers rolling out their own discounts this week include department store chain , which is holding its "Penney Palooza" sale online again this year. Around Prime Day last year, Penney's event brought roughly a 13 percent increase in the number of visitors to its website that became buyers, compared with the retailer's daily average, according to a report from Multichannel Merchant.
"Amazon Prime Day is creating a 'Mobile Black Friday in July' for many retailers, especially those taking advantage of the excitement around Prime Day to launch their own online and mobile promotions like JCPenney's Penney Palooza sale," GPShopper co-founder Maya Mikhailov told CNBC.
"We have consistently seen visits to our clients' retail apps and their conversion rates increase on Prime Day, and we expect this year to be no different."
Some of the rival retailers' deals will start before the core Prime Day offers begin and last even longer.
For example, Toys R Us announced Monday that all of its customers will receive 20 percent off purchases made on Toysrus.com and Babiesrus.com, for 36 hours, starting at 6:00 pm ET and running through Wednesday. The toy retailer also said in its press release that no membership is required.
Department store chain Kohl's told CNBC it will be offering 30 percent off some of its summer clothes, swimwear, sandals, accessories, beach towels, outdoor toys and patio furniture on Kohls.com for 30 hours straight.
Best Buy is preparing to roll out its competitive deals — which include $200 off a Dyson vacuum and $70 off an Apple Watch Series 2 — on Tuesday and keep those prices in effect all week long. Notably, while Amazon will be promoting its Echo device during Prime Day, its rival Home will be sold at Best Buy for $99, starting Monday.
In its third year, and coming at a uniquely competitive time for the entire retail industry, Amazon's Prime Day "underscores the retail transformation, especially toward digital," PwC's Barr said.
"This is an all-out battle for relevance and market share."