All the ICO-rating site have package plan for any ICO being listed on their website which varies from premium to free rating. Some premium rating are the paid rating that you are talking about. Some of this site even have advertisement banner to promote some site being listed on the website. However investors should know that ico rating site is not enough in accessing any ICO.
You need to do your own research before taking part in any ICO! it is no more news that some top rated ICO have turn out to scam...