You can now pre-order Windows 10 on Amazon — but if you don't like waiting (or if you like free things), you might not want to.

The July 29 release of Windows 10 is fast approaching, and by making it available on Amazon, Microsoft is making sure customers can buy it however they want. But both the $120 Home and $200 Pro editions of Windows 10 will ship August 30, a full month after its release as a download on the web.

And many people won't even have to pay for it. Windows 10 will be a free download for one year to anyone currently running Windows 7 or 8.

Microsoft's new operating system will ship on a USB stick when it ships from Amazon, and hasn't even appeared on Microsoft's site or at the company's retail stores, though it's expected to show up there soon.

However, while upgrading for free will be the preferred choice of many, owning a physical copy could provide some advantages. It means you'll always have a fresh, bootable copy at the ready in case you ever want to reinstall a clean copy.

The USB stick launch is also another sign that the disc drive is close to being dead. New Windows releases have typically come on discs. But millions of Windows users have long dispatched with them after moving to ultra-thin laptops that don't carry them. Those computers still have traditional USB ports, however.

Microsoft is looking to right the ship after it turned off a chunk of its users with Windows 8. That operating system tried to combine a tablet-style interface with a traditional desktop. With Windows 10 (it skipped Windows 9), Microsoft is adapting the traditional desktop with a more modern look made to work across devices.