If you are thinking to try Windows 10 on your PC, or to try Dual-Boot Windows 10 with Linux, it is not necessary to buy a Windows 10 license. You can download Windows 10 from the internet and use it free with just several minor limitations.
Preparing Windows 10 Bootable USB/DVD
To install Windows 10 you don’t need any serial number. Earlier when Windows 7 appeared you had to own a serial number before even starting to install your Windows. Now everything has changed.
Microsoft even is giving a free tool that will help you to create a USB bootable disk with Windows 10 or a bootable DVD with Windows 10.
First you will have to download Windows 10 by using this tool from here. I would recommend to download the DVD image of the Windows in the ISO format. Also you can choose your Windows language, Windows Pro or Home edition and the 32 or 64 bit version.
Now, to create the bootable USB stick or bootable DVD, you will have to download this tool from this address. It is free and you need just to follow the steps.
Installing Windows 10 Without a Product Key
When you choose the right Windows 10 version that fits for you and your computer, made bootable installation USB stick or DVD, you can proceed to installation.
When installing Windows 10, at a some step you will be asked in “Activate Windows” step to write the Product Key. As you didn’t buy any and do not want to activate it you can skip this step by clicking on: “I don’t have a product key” on the down right side.
The Windows 10 installation process will continue and you will have Windows 10 fully functional and unactivated.