Wal-Mart has B&M locations that you travel to (and if you've seen a sitcom in the last 30 years you know that "just go to New Jersey" isn't a popular solution for New Yorkers). Amazon ships the stuff to you. Now they do it in an hour, if you're in New York. That's as long as it would take to get to Walmart and back, except you can continue living your normal life instead of driving to New Jersey.

(Also, New Yorkers don't drive. So that Wal-Mart in New Jersey is closer to an hour away by transit.)