Regestering original works

I don't worry with copyright.... at least the Library of Congress kind. It's a per song.... I forget the current price because I don't use it.
 
My publisher handles that registration process for me when they sign my music and I don't have to pay.
 
That's not to say I don't protect my music because I do. I use a program called MasterWriter. It is lyric writing and organizing software which comes with what appears to be a lifetime access to their SONGUARD service. So I can register as many songs or snippets of songs as I want at no cost as a registered buyer of Masterwriter.
 
Masterwriter is available on a monthly or yearly reduced cost license fee.... or you can pay $200 to own the license outright.  If you write a lot of music this is the way to go.... I register completed songs, things I work on with others and even instrumental music on Songuard. It's cost me about $2 per song with the number of registered songs. 
 
 
On the other hand.... depending on your writing abilities, most folks really don't need to worry about someone ripping your songs off. It's a very rare event and the music generally has to be well written to bother to rip it off.  Why rip off something that won't be sell-able?
 
When you post something on the internet web sites, the servers there record all the important things, such as date it was posted and time.  That info remains tagged to the file. It's a low level copyright date of creation kind of thing. Basically, that's all the LOC copyright is as well.  The only useful purpose for the LOC copyright is if you have to go to court, as the courts will ONLY accept the LOC copyright info for FILING the case.  A third party service, as long as it is secure, a competent lawyer would have no problem proving you created the song in question.
 
Oh yeah, regardless of how you choose to register it (or not) you should always include the copyright symbol or the word COPYRIGHT plus name & year on everything you post.
 
Copyright is automatic under the law when a song is rendered to a medium such as digital or physical for listening of the general public. The LOC or other is a formality so to speak that proves it.
 
Hope this helps.