"How much money for the school supplies?"
Translation:ʻEhia kālā no nā lako kula?
“O” is for o-Class possession. Conceivably there might be English usages that confuse the two, but I think the difference is usually pretty straightforward.
It might help to think of the words as an arrow: “a/o” are like an arrow pointing left, while “no” is like an arrow pointing right. At least, that’s how my pea-brain pictures them. :-)