Amazon has its own line of smart TVs, and this 40-inch model is marked down more than 30% ahead of July 4. It offers high-definition 1080p resolution, and it's equipped with the brand's Fire TV streaming platform, which gives you access to live TV, video games, and music, as well as apps like Netflix, Prime Video, Disney+, and so on.

To Walmart's credit, it was Amazon's closest price competitor in most of the Profitero study's categories, "most aggressively" when it came to appliances. Walmart has gained a little ground on price competitiveness in the electronics category in the past year, but lost some of its edge with video game prices.

The most popular stores, like Walmart and Target, are holding their own competitor sales during Prime Day. Here are all the sales to check out