Amazon's Prime Day is 4 days this year, and Walmart is fighting back with a week of deals of its own. How to score the best bargains this year.

The Amazon Fire HD 10 tablet is an excellent tablet. You can read books, surf the web, and watch videos, and unlike the Apple iPad, it's less than $100. Heck, today, it's only $70 — a whopping 50% discount from its standard price. This is the lowest this tablet will go, probably even cheaper than you'll see at Black Friday.

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.