Those are loss leaders. Much like the 29c/lb turkey at Thanksgiving, or the $29 laptops the day after, these deals are designed to get consumers into the store

Those are loss leaders. Much like the 29c/lb turkey at Thanksgiving, or the $29 laptops the day after, these deals are designed to get consumers into the store or website, so each will buy 1 or 2 and several other items and accessories. High-margin accessories like USB cables and wireless mice, or potatoes and stuffing, easily offset those loss leaders. The entire point of the 2 item limit on deals like those is to prevent companies from doing exactly what Backblaze has done. By snapping up all of these deals, they're reducing the number available for consumer purchase, which impacts the revenues of these big-box retailers. Basically, Backblaze absorbed the (economic) consumer and retailer surpluses for HDDs in the Bay area and passed it on to their consumers.