There are millions of web sites with millions of web pages and thousand being developed everyday. A critical stage of developing a profitable web site is submitting your web site to as many sources as possible.
All search engines offer free registration.
You can register your site yourself. Many of the free and pay registration websites will register your URL with all these search engines. For a modest fee, registration services will save you lots of time, register your site with hundreds of search engines and may offer you other valuable services. Many of the pay for registration websites offer FREE limited search engine submission as an incentive to purchase other valuable services. Check out their sites for free services.