"I Give Away!"

Founded in the US in 1926, the initials actually stood for the International Grocers Alliance, but their "I give away!" slogan sure got people's attention. The ad dates from 1955 by which year Ottawa/Hull had over 30 affiliate stores, operating on what was more or less a franchise basis.

Wikipedia has a decent overview of IGA's presence in Canada here.

Where Once a Woolworth's: 47 Rideau

 Some of us remember when 47 Rideau was a Woolworth's store, its lunch counter snaking along the east wall, the perfect place to grab a hot dog, french fries and a Coke, then spend the rest of the afternoon burping.

Woolworth's was first listed at 53-55 Rideau in the 1915 City Directory. The store was expanded in 1945 — frustratingly, I have not been able to date the Deco facade, though it somewhat resembles the one designed for Woolworth's 1941 Sparks Street renovation (since demolished), supporting the idea that it dates to the '45 build.

The Ottawa Journal, December 8 1944

Chapters opened at the old Woolworth's location in the fall of 1996 — frightening how a quarter-century breezes by. Chris Ryan offers more details on that subject here.