I fly over 100 000 miles a year to races, most of it with a bike and most of it on Air Canada. $50 each way, $0 if you have Super Elite status. Sometimes $0 with Elite, they can't make up their minds and it depends on the mood of the check-in agent.
When you pay the bike fee, the max weight limit should be 70lbs, not 50.
Be VERY careful with Qantas. I had to fly home with Bryn and Jill's Norcos from Africa because it was going to cost them upwards of $1600 to fly them back to Oz, despite the "sports equipment is free" assertion. It cost me nothing for 1 Overweight Ogio and 3 bikes, on AC.
United will vary between $100 and $350 depending on what excuses they make that day, and Swiss/Lufthans will make you go broke.