How about a giantess wife?

Over the years, one of Tom's favorite types of porn was pretty...unconventional, the kind of thing that was limited to the world of imagination without his coin. Specifically, it was erotica involving giant women. There was a lot of it out there, too, and Tom had devoured and masturbated to a lot of it. Hell, he has even had a dream of Sarah growing into being the size of a skyscraper, able to wreck the city to her heart's desire, with no one able to stop her.

And with this coin, he could make that dream a reality. Now, how was he going to do this? He could start it off by starting slow and having her grow over time, or he could just skip straight to the giantess level.