The link provided gives a great idea. But you can save a bit of money and still get rock solid protection by using 6" drain line. Its the green pipe used for waste. I think a 10' stick will run you around 12 dollars. Thats 70" or so for the bow case and another section for an arrow shipping tube.
You can buy the caps or use a jigsaw to cut out wooden ones to screw inside the open ends. Or one glued on cap and a wooden removeable one on the other end. After you cut the bow tube ad arrow tube to length, you have a short piece to use as a template to mark out your wooden ends. A regular crosscut saw will cut the pipe no problem.
My recurve wrapped in a small blanket fits snugly insude a 6" pipe, no movement at all. Used an old couch cushion and cut some round pieces out for padding the end. And if ya want the tube back just have em figger the return shipping without the bow inside and send along the necessary postage.
Even the post office can't hardly mess up a case like that,I still get insurance though!