Websites (crappy ones) could cost $50 initially if all they are is static content or generated in some uniform way without human involvement. They won't be web applications, they won't look novel or unique, but it will be a web site, a meager web presence. Obviously many people don't come in asking for this option, but it is an option. If the client only has $50 they're going to have to lower their expectations.

We can all get together and complain that there shouldn't be $50 web sites but if a client is asking for one and knows what it means then yes, there should be $50 web sites.

These people will not be gone soon. There are many people still starting their online presence, still understanding the online world, and there will continue to be as more and more people are exposed to the ability to connect to the internet.