Google said “if you’re out and about and near a store that carries those boots, you might see a Google Now card showing you the product and price to remind you that you wanted them.”
Imagine you search for a specific product on Google and then you are driving or walking past a store on the street that has that product. Imagine Google pops up a Google Now card to tell you the store has it and the price of the item. That is incredibly futuristic stuff.
Here is a picture of what the Google Now card may look like: