I want to add custom search option in my website.

Can anyone help me in adding a custom search option on the website? Now I am using google API for such functionality. But this API has some limitations. It can allow only 100 to 200 requests. After that google asks for payment. So is there another way to achieve such functionality and used it on our website. I am using a proto template.
The template which I have purchased only has the page to show search results which is static. If you click on the search and enter anything it will show the same output.
It will be a great help if anyone helps me in achieving search functionality.

Thank you…