An au pair is mostly paid in room and board (own bedroom and all meals provided). They are also given an allowance from $190 – $280+ a week *.
(*dependent on age, experience and number of hours help needed, from < 25 hours to 35 hours).
But this is not the only expense when hosting an au pair. Generally there are number of additional costs.
See the other FAQ – What other costs do we need to think about?