Lapraniteon

Hello, I'm gearing up for my first PC build and was just wondering about something. The Windows 10 Home licenses on pcpartpicker are listed for about €120,-. When I go onto Google, however, there are keys available for €10 - €20,-. What are the differences between the two? Are there any added / unnecessary risks? What should I do? Not supporting piracy, just debating whether I should pay a full €100,- extra for an "official" copy? Any help is appreciated! PS: Attached are examples of those cheap key listings.