Look for "amazon fulfilled" tag, it mans amazon is responsible for handling & delivery of product with seller's role only to hand over the product to amazon. "Prime" tag means that product is eligible for Prime members benefits & this tag is only given to usually big &/or reputed sellers as prime members are paying members of amazon site. Every "prime" eligible product is also automatically "amazon fulfilled" but reverse is not always true. Check a seller's rating & it should be at least 80%+ with at least 100+ reviews in last one year(the more the better). Buy hdd/pendrives/sd cards etc from appario retail/cloudtail as these are amazon own sellers. There are some good pc components sellers also on amazon for stuff like processors,ram,mobos etc like A1price A1products,TPS Technologies etc.