What is an average wage in the USA ?

For which profession?

$41, 211.36 according to the Social Security National Average Wage Index. Source

Welcome to Fluther.

This is a nearly impossible question to answer with a single number (as @marinelife has gamely attempted), because professions and experience are so varied, hours of work vary tremendously, and wages differ from place to place because of other factors that make some areas have a higher cost of living.

So here is a link to a Wikipedia article that may help you discover some other “measures of central tendency” regarding wages in the USA.