Tuition Fee
Beyond the Grave was an extremely broken ability that the Inn had gained, in Lex's opinion at least. While it did not completely revive a dying person, it allowed them to continue to exist, at least in some form, for a limited duration of time.
When Lex first read about it, one of the fears he had was that once this became widely known, the Inn would have more ghosts than actual guests. After all, people die every day, and if they discover a way to continue to live, even if it was for a short time, he expected many people would avail it.
Yet his worries seemed unlikely, at least for the moment. This was due to the fact that the only guest who had used the ability so far had spent an enormous amount of money - a truly stupendous amount - and gotten 13,000 years.