Small income from tutoring last year, where/how do I report/claim this?

My wife had a very small amount of income from tutoring last year ($150), all in cash or checks.   This is not a business but just something she does on the side for some extra money.  Is there a minimum amount to claim this?  If the amount doesn't matter, how should I claim this?

 

Thank you for your help,

 

Rob S.