This has come up in the past and so I thought I'd post a quick resource.

Often when you create a blog post (particularly if it's part of your funnel) there is a lemming effect, in which no one wants to engage until there is a certain amount of existing engagement. And so it can take some time to build up some base engagement.

However there is a solution. You can simply pay $5 on Fiverr to get some initial comments, so you are not sending your paid traffic to a blank canvas.

For example: Here are a number of gig options that will get it done: https://www.fiverr.com/search/.....ayout=auto

HOWEVER, depending on how you use a service like this, it could be considered an ethical grey area. I would never suggest using these comments to make claims, or use as testimonials, or create an illusion of something being true that is not. In fact I don't use them at all because I have a large mailing list and a single blast usually gets more than enough comments rolling in. 

However, I can definitely understand how hard it can be to get that initial activity to take place on your site, and so for those of you who are just starting out, this might be a simple and cheap way of kickstarting some engagement.