This week Walgreens announced plans to buy Rite Aid in $17.2 billion transaction that’s expected to close next year. The deal could have a direct impact on Potomac Village, where Walgreens and Rite Aid have stores right across the street from each other — and one would be likely to close. Walgreens currently has more stores than any other U.S. drug chain, but rival CVS — which recently announced plans to take over Target’s in-store pharmacies — does a bigger business in dollar volume. The Rite-Aid acquisition would potentially give Walgreens greater purchasing power to cut deals with its suppliers and possibly offer better prices to its customers.