Cheap Discount Travel

I Want My Mom To Come Visit To See My New Baby Girl Sometime Around Spring Next Year. If Its The Other Way Around I Could Get Tickets From Tokyo To Denver For 700 Dollars Total. But That Is Through An Awesome Travel Agency I Found Here. I Have Checked Expedia, Hotwire, Orbitz Ect.. Without Any Success. Is Their Any Other Place Travel Agency Or (anywhere!!) That I Can Find Good Discount Travel? And What Would Be A Cheap Time To Fly. Thanks For He Help!!