is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a specialist in web pages images, information and other types of files. Some search engines also mine data available in database or open directories Unlike web directories which are maintained only by human editors, search engines also maintain real-time information by running an algorithm on a web crawler
The very first tool used for searching on the Internet was Archie The name stands for "archive" without the "v". It was created in 1990.Later Magellan, Excite Infoseek Inktom, Northern Light and AltaVista . Yahoo was among the most popular ways for people to find web pages of interest. rather than full-text copies of web pages. Information

What is the cost of running a search engine?

It depends how big and popular your search engine is. If your planning on the next Google, get ready to spend millions daily on running it (then again, if you were to start the next Google, I'm sure a few million dollars is not much).