11 points
*
It’s actually not plural, but rather possessive.
It’s an example (I think) of a snowclone.
8 points
You’re definitely right about the possessive thing. I’m not sure about the snow clone. I always thought of it like they were treating the name of the store like the last name of the family who owns it. So it’s like a shortening of, “we’re going down to the Aldi’s store.” As if you’d walk in and Mr. Aldi would be behind the counter.