Question windows 10 - b350 prime asus? building new pc

[TMBlair]

Hi,what's the cheapest way to add a windows 10 onto a new asus b350m prime ?

can i download windows onto a flash drive then buy a product key for 20-40£
or would it be better to buy an ssd drive with a windows is this the most value,quality affective build ?
are there any methods that i can trust? cheers

 

[SkyNetRising]

You can install and run windows 10 unactivated.

 

[ElectrO_90]

If you go to Guru3d.com (a well trusted website) they are doing Windows 10 for like $12

USB is the best option