The Starving Ghoul
This is a screwball story from Eerie Publications' Terror Tales #7, March 1969. The title, "Gravestone for Gratis" has nothing to do with the story. Neither does the splash. They look like they've been stuck on from a different story. Other than that it's pretty typical of an early '50s horror comic from which it was reprinted. I don't have the information on its original appearance.
The writer could have let us know early in the story the main character had a medical problem so the plot device at the end wouldn't be so jarring. And speaking of "jarring," the cover is a gruesome Eerie Publications classic.