'find' is actually crazy powerful. it takes a lot of switches.
the actual syntax currently looks something like this:

/kiosk find [buying|selling] <needle> [-price <comparator> <value>] [-ench <enchantment> [<comparator> <level>]]

probably wouldn't hurt to include examples:

/kiosk find selling cobble -price < 2.50
/kiosk find selling diamond sword -ench looting >= 3