Help to find the cheapest airfare for an unaccompanied minor Please..?

My husband has not seen his child for a few years now and the mother has agreed for his baby girl to come visit but it has to be before school starts on the 4th of Aug. he has already taken the time off of work from Mon-Fri the28th-1st and we just got paid and still don't have over$500. dollars to get her here are there any other ways possible?