Does Cakewalk sell the upgrade for Melodyne editor through the command center or in its store or do i need to I buy it from a third party?
 
If I need to buy it from a third party,
Any good links on where I can purchase the upgrade to editor from essential for as little $ as possible?
 
Thanks :)

I got the editor upgrade through Celemony, but I did receive an email with a good offer.  Have you tried doing a web search?

I would check Cakewalk store if they have specials for that.
 
Otherwise $209 at www.audiodeluxe.com.

When the upgrade is applied, you won't download anything, just unlock the hidden functions from the melodyne you have installed. You actually have the full version, but with parts lock down.

Some of us have had good luck emailing Celemony and asking for an upgrade deal since you're a Sonar user.

Celemony has fast, real, tech support.  The full version is a great product.   

The Editor is incredible. I've been able to fix things with it that were otherwise impossible. For example; I had a live recording of a 3-piece group (guitar, bass, and drums) where on this particular song there was a 4-beat intro count and the drums and bass came in just ahead of the 1 beat (anticipated) but the guitar player (me) forgot and came in on the down beat. It sounded pretty sloppy. With Melodyne Editor I was able to actually drag that one guitar note IN THE MIX to line up with the bass and drums and you can't tell it wasn't recorded that way.
 
Another example; I play acoustic fingerstyle guitar and sometimes a string will vibrate against a fingernail causing a zinging sound and I have been able to remove those without leaving any audio gaps.
 
I bought my upgrade through Celemony for $149 on 5/29/14.