How much does the Hacker News API cost?

You buy credit packs (or use the 100 free signup credits). Most routes — search, feeds, stories, items, user profile, submissions, comments, favorites, updates, maxitem, and Who is Hiring — cost 1 credit per successful request or page. Story comment paging costs 3 credits per page and comment context costs 2 credits per request. Always check meta.creditsCharged on the response.