Some items display that the price is 0 sp (as if they were unavailable for purchase) here: https://freeimage.host/i/qF7S5Al, but actual search in user shops shows correct prices: https://freeimage.host/i/qF7SOV1. This is the 2nd time I encountered this today, forgot to take the screenshot of the 1st item. There are most probably multiple items like this.

We already have a few topics about that here and on Subeta. In the beginning there also were 0sP items on Shop Search, now they only seem to appear on Kumos quests. I ceased posting the items yesterday. It has been going on for very long.