But, Keller Williams Agent Websites Cannot Be Found in the Search Engines...

This is completely false.  This website you're looking at can be found on the search engines, including Google.   For example search for "Keller Williams Agent Website SEO" since that is what this site is about.  It is listed as #1 in Google.  It also ranks #1 for a bunch of other terms like "KW SEO Manual."

It can be done.  It's not much work.  You can save money.

Follow the techniques listed here and your site can be found in the search engines.  It takes work to rank for highly competitive keyword terms - so don't think that if you want to rank for "New York City Real Estate" you're going to be able to set your page title keywords and the leads are going to come rolling in...that is going to require some effort to get other people linking to your site.  However, if you pick a keyword that's a bit smaller in stature, you should have no issues showing up the in the search engines and ranking well.