(Charles Krupa | The Associated Press) In this June 4, 2014, file photo, people walk in to a Walgreens retail store in Boston. Walgreens gave investors a better-than-expected third quarter, raised its dividend and detailed a big share buyback Thursday, June 28, 2018. But shares of the nation’s largest drugstore chain and its competitors tanked after Amazon.com took another step into their territory by announcing the purchase of PillPack, a relatively new online pharmacy that offers pre-sorted prescription dose packaging and home delivery.