I want to ask someone for a clarification of his answer to a question of superuser. But when I try to ask the question, it says I need a "level 50 privilege", whatever that is. Is this a paid-subscription website?
No this is not a subscription based website. You need to have a certain reputation for posting comments. This is simply to ensure the quality of the site.
As @DavidPostill suggested. Please refer to the help section:
Posted this as an answer in the light of making sure everyone else interested notices it.