I was in Niagara Falls New York on the weekend and stopped into Tops Markets.  While wandering the aisles I noticed prices were about the same as Southern Ontario; that is until I started looking at staples.

By staples I mean bread, butter, milk, eggs, sugar, flour.  I pay about $4.79 for four liters of whole (3.25% fat) milk, Tops was selling a gallon for $1.99.  I pay $1.99 for a dozen large eggs, Tops had them for $0.99.  I pay $2.97 for a pound of butter, Tops was $1.69.  Basically Tops shoppers are paying half of what their northern neighbours pay.  Ouch.