Walmart has just updated its Flash Deals section with a new batch of deals for this week. New offers include up to 30% off mattresses and back to school essentials, and up to 25% off air purifiers and dehumidifiers. There are lots of great deals in the Walmart Resold section, too, where refurbished tech reaches best-ever prices. It’s worth noting that the discounts within almost always exceed what the banners indicate. Shipping is free for orders over $35; otherwise, a $7 fee applies.  These deals will end on July 17. Shop Now at Walmart