Government Edition for Custom Search Engine is now available for free without Ads for Government agencies or bodies at any level (federal, state, local, or tribal).
Please note that the free usage of Custom Search Engine applies only to the client side Custom Search Element. Using the JSON API will still cost $5 per 1000 queries. You must obtain a Gmail account to be able to perform the following steps.
STEP 1: Get your new search ID by visiting the Google Custom Search (GCS) service landing page
STEP 2: Review the GCS instructions page to help configure the new search collection
STEP 3: Once you have the new search collection ID please fill out the government advertisement exemption form
STEP 4: Update the search ID on your website once you have confirmed that advertisements are not showing in your Google Custom Search Console results