How much does the Google Ad Library API cost?

You buy credit packs (or use the 100 free signup credits). Each Google operation is priced in the API registry — amounts appear on the endpoint pages linked from this hub. Company ads pages can cost more than a single advertiser search; each paginated page is a separate billed lookup. Confirm every response with meta.creditsCharged. There is no required monthly subscription for pay-as-you-go packs.