web.archive.org.

I'm surprised I had to scroll down this far to see the obvious.

If you need cached versions of websites, just use the InternetArchive and make sure to donate.

It also should be obvious that only a small portion of all pages of the Internet are in InternetArchive.

Yes, it is. I admit it's not a solution for today but relying on a free service by a major corporation that won't accept direct payments for their search service is not a long-term solution.