It looks like the software that runs a hardlock dongle: a piece of hardware that is used to prevent software piracy on certain programs. If you don't have anything like or connected to your compuer, you probably don't need it.
The verizon 4S wouldn't work because it's not LTE capable, so there's no FCC agreement and it's not unlocked. For a used phone eBay, amazon, and Craigslist would be your best bets. But the prices aren't that great comparitively with new tech.