What restaurant once used the motto "Buy Them By The Bag"?

From 1927 to 2008 "Little Tavern Shops was a chain of hamburger restaurants in Baltimore, Maryland, and Washington, D.C.... The slogan of the chain was "Buy 'em by the bag", and its signs promised "Cold drinks * Good Coffee". The stores were quite small and could accommodate only a few seated customers, while most business was take-out."

https://en.wikipedia.org/wiki/Little_Tavern

Correct.

http://silverspringhistory.homestead.com/LittleTavernThenAgain.html