As the ice cream parlor server weeps openly and confesses all of his or her sins,
still producing a flawless
Peach Melba.
The cost probably will actually be non-negligable though: This is a mostly non-industrialized world, mostly subsistence rather than cash crop agriculture. It has an
extremely anemic trade network from what I have seen and Villages are only just now starting to get their feet under them economically. When they have something they can export in any bulk it seems big enough that they are willing to name
countries after it.
Ninja, even lowly genin, are going to be
goddamn loaded compared to, well, nearly everyone on this godforsaken rock, so its manageable... but vanilla? The heavily refined product of orchid beans? Yeah. At the very least it will be the sort of thing a teenager gets his significant other on valentine's day or the equivalent.
Your average peasant wouldn't know that vanilla exists, even if he vaguely knows that merchants have a way of making ice and chilling produce any time they want.