The documentation for Google Custom Search JSON/ATOM API is unclear regarding pricing for additional queries. It states:
The API provides 100 search queries per day for free. If you need more, you may sign up for billing in the API Console. Additional requests cost $5 per 1000 queries, up to 10k queries per day.
For those that use that API in excess of the initial free 100, does the $5/1000 additional queries reset each day, or does that number roll over for subsequent days?
For instance, if I have a total number of queries on 3 consecutive days of 110, 120, and 130, will the account be billed $5 each day for the 10, 20, and 30 extra queries? Or will I be billed $5 the first day and by the end of the 3rd day I'll still have a bucket of 940 additional queries left to use for future overages?
In case anyone is also still looking for an answer to this question, (as I was a day ago), it turns out that for the Google Custom Search API the billing for $5/1000 queries is prorated. Google Cloud Support emailed me the following:
With the Google Custom Search, you have a free 100 search queries per day which resets daily. But for example if you exceeded the daily limit, you will be charged $5 per 1,000 queries. In case that you go over the 100 queries per day and did not reach the 1,000 queries, it will be prorated from the $5. This resets daily as well. Please take note that 10k queries is the maximum daily.
I then clarified with them the following example, which they agreed was correct.
An example of making an average of 180 JSON API queries/day: