asking price, price set by a seller without discount or other alteration

"good age", used in pointing out that someone is doing something below their age group

not necessary to; don't have to

If only ~

It's good / okay to... / is fine

what

What?, Huh?

what / that thing (used in place of words you can't remember at the moment.)

what number, how many (used with a counter) / (used with も) many (used with a counter)

something