As an Agency how much can I expect to make selling this Video Service?
This of course is entirely up to you.
I can tell you that I recently setup up my own website as a Video Agency for Small Businesses. To one business I offered to create and install a video for his business using Video Avatar Pro. I asked $850. This was with no Call to Action option at all.
He instantly said yes and bought two ($1700). My total cost for hiring a Professional Actor on Fiverr to do both videos was about $200 plus I gave her a $100 tip at the end just so I would not feel so guilty about the margins I was getting off her work.
You can ask anyone that knows me and they will tell you I am a terrible sales person. And they would be right.
This should give you an idea of the potential.