One successful request, not one mention
Each successful archive retrieval costs one credit, including a response with no matching records. The rate is $1 per 1000 successful requests, or $0.001 per credit. A $50 minimum paid top-up adds 50000 credits. The maximum of 100 records in a request does not mean one credit per record. There is no subscription, and paid credits do not expire.
One successful request for the BuyItForLife backpack example costs one credit whether the page contains zero, one, two or three records. Reviewing those records with a second analyst or revising local codes does not call the API again. Fetching another page or rerunning the query is another retrieval. A useful budget therefore separates collection calls from analyst time and from the number of coded statements.