Bike shipping box

I was wondering if anybody could recommend a good, solid shipping box that will accomodate a tri-specific bike, and that doesn't cost an arm and a leg. With the horror stories I've heard about shipping a bike through the mail/FedEx/UPS/etc. I think I'm going to bring her on the plane with me. However, most of the boxes out there I've seen are $350 plus - It seems odd to quadruple my race entry fee just to have my bike there. Is that the norm for a good shipping box? Any recommendations would be most appreciated.