Buying the adapter alone will set you back $24.99, or you can get it bundled with a controller for $79.95. Is it worth it? That's a tricky one.
We previously named Sony's DualShock 4 the best controller for PC gaming, though there wasn't much in it between that and the wired Xbox 360 controller as a budget option. A large part comes down to personal preference, so it's worth taking a peek at that article to work out what will have the most appeal to you. The main advantage of Xbox controllers is that they just work, with no need to fiddle around with additional software (unless you count potentially installing a whole new OS). That said, Tyler didn't have much trouble getting the DualShock 4 to work seamlessly, and we've got a handy guide so you can do the same. The jury's out on how easy it is to get it working wirelessly though.
If you're after a good wireless controller that's easy to use, this might be the way to go. Unless, of course, you're not in the business of swapping OSes just to get a controller working.
You can read our review of the Xbox One controller here.