Or... you buy it as a parts car, or check the body to make sure it's not rusty. And then you get it for practically free, with the expectation of having to rebuild everything. I hardly ever see any running, let alone driving W116's for sale--and those that are, are usually a mess, and they almost without exception end up in a wrecking yard and get picked over by me. Properly maintaining a W116 can be a Herculean task in dollars and/or time, unless a person is really dedicated and knowledgeable.
I don't really care so much about mechanicals, as I figure everything's going to be worn out on a car this old, anyway. The condition of the body is the most important thing to me. Of course, if I was going to be spending any real kind of money, that would change. I usually buy my cars completely broken and slowly nurse them back to health. I actually have one non-W116 Mercedes project that I'm going to make from cutting two cars in half and welding them together. And patching up rusted-out panels. Did I mention there's no drivetrain, either? It will all come together eventually.