If you have gotten a laptop in the last decade, it likely came with a WiFi adapter. That is also true of some desktop computers, but not all of them. What happens if you have a WiFi adapter that isn’t as fast as you’d like or simply stops working. In those situations, having an adapter that plugs into a USB port would be awesome.
The Motoraux 600Mbps Dual Band Wireless USB WiFi Adapter is a very good choice as it supports really high speeds and comes with a nice antenna to give you stronger signals. Is it the least expensive option? No, it is not. There are very small adapters that sell for under $10, they their size doesn’t allow for the big antenna. So the current selling price of $23.99 at Amazon seems like a good deal to me for what you get.
It works on Windows XP, 7, 8.1 and 10 both 32-bit and 64-bit versions. It also is supported on Mac OS X 10.7.X and higher. This might even be one of those gadgets you have in your bag just in case you ever need it.