When someone opens a page with JustComments widget, the widget will fetch up to 100 top-level comments and additionally all replies to those comments.
Creation of comments and storage of comments is for free.
You top up your balance with credits you spend if
your readers fetch the comments. Estimate the costs using the slider.
500,000 of credits
For example, you got a site with 25,000 pageviews per month. For example, only 80% users scroll down to comments so this reduces to 20 000 page-views. It would cost 20 000 credits or just $0.3 per month. if you have no more than 100 comments on each page.
JustComments is already optimized to request comments only if the user scrolls down to the comments section. Of course, you are free to include the comment widget not for all users but only for those who request to view comments.