A strip mall is a small outdoor shopping center with one or two "anchor" stores like a grocery store or department store, and maybe a dozen or twenty small shops and offices. It is usually located in a residential ares.
En masse is French and means exactly what it sounds like. We use it to mean in bulk or all at once.
The crowd turned en masse toward the balcony.
That tire thing was probably meant as a spoof of the old joke where the unsophisticated merchant does his own TV commercial and says, " Our quality and prices are the lowest in town" or something like that.