Everything was 10 to 30 bucks cheaper, per item, in the store, which is actually a John Deere dealership, but they carry Stihl stuff as well, that's how it works where I live, than what it showed online, through the Stihl dealership website. The guy mentioned that's what a lot of folks do is just add a blade and adapter stuff to the string trimmer, but for 35 bucks more, for the whole attachment, this just made more sense and now I have an extra attachment, just in case one breaks.
I use a manual Stihl P800 pole saw and have the pruning head with it as well. I was going to get the pole saw attachment, but for 200 plus bucks, when I already have a manual one, I figured that money could go towards a 394, and new 3120 instead.