Cheapest Way to Get a One Way flight from Kiev, Ukraine to the US (Salt Lake CIty)?

Its an emergency, so please no joking. My girlfriend, is in Ukraine and needs to get home before the end of her study abroad, she just had an appendectomy and needs to be back in the states. Currently she is in Kiev, Ukraine and needs to fly back to the US as soon as possible preferably into Salt Lake City, Utah or Boise, Idaho. The cheapest flight I have found is 630$ does anyone know of anywhere cheaper? I know if you book flights in Europe you avoid the taxes and fees that you have to pay in the US. Please help