Google has provided an easy way to search your site, be it free or paid with custom search. The free version comes with Google ads that relate to your site, but not limited in other areas like other third-party search engines. If you have a tax-exempt business website according to Google’s guidelines, you have the option to turn off the ads.
You can customize the whole search experience and everything needed through the Google Custom Search engine site. It requires very minimal setup to your website with simple copy and paste code. With Google hosting the search engine, you don’t have to setup any background files or plugins on your own web server and maintain it.
It works well for search engine optimization and your website rankings, since it gives the ability to work with Google Analytics. You can see what people are searching for on your website to help improve or update it and get maximum results.
NOTE: As of April 1st, 2017, Google discontinued the sales of Google Site Search, the paid version of Custom Search Engine. This product will be completely shut down by April 1st, 2018. This note does not affect Custom Search Engine.