Official FAA Unmanned Aircraft Systems (UAS) Registration Linkstan
Like everything else there are many “Register your done sites” That look official, but they are not, they are services that will charge you more to register your drone because they are a service and not the FAA direct.
Its easy to get registered and save them money. If the site you are on does not have “www.faa.gov” in the address its not the official site! Don’t be fooled and dont pay for something you don’t need. The process is straight forward.
Here is the official FAA Unmanned Aircraft Systems (UAS) Registration Link.
Have fun and safe flying!