In commercial transactions, the quality of goods and services increases as the prices increase, i.e., the more one pays, the better the merchandise.

Alternative form of what do you want, a cookie?

I can't help the way I am

What are the languages which you can understand and which you can speak or write in?

If something is acceptable for one person, it is acceptable for another (often of the opposite sex). / One who treats others in a certain way should not complain about receiving the same treatment.

Used to allude to something unsaid or hinted at.

(informal) An expression used to point out that another person's joke or cleverness has been recognised or understood, either to acknowledge its cleverness or alternatively to communicate a lack of amusement.

(formal or humorous) A question asked to know the reason for being visited by the interlocutor.

(colloquial) You are familiar with the situation I am describing; used to establish common ground with the interlocutor

Literally, what is good for a female goose is equally good for a male goose (gander); or, what is good for a woman should be equally as good for a man.