I was once shopping for an office chair, and since you can't tell what a chair is like to sit in by browsing online listings I went to Staples to try out their chairs on display. I found one I liked, and was ready to buy it. On a whim I used my phone and the store's wifi to look up the same chair on the Staples website, where I found it on sale for less money with free delivery included.

Still sitting in the chair in the store I ordered it online, saved some money, and then went home without having to take a heavy chair with me on the bus.