OK... for recurves... which really are a bear to ship. I used to have a collection of vintage target recurves, and selling those and shipping them when I gave it up for longbows (the only way to fly... when will the rest of you learn?) was a real ordeal.
I made cardboard boxes out of many an appliance box. Neat tool trick... get a plastic pizza cutter. Work out the dimensions you need and mark where the folds will have to come. Use a long 1x2 as a straight edge and compress the cardboard on the INSIDE of the fold by running the pizza cutter over the line, pressing down hard. The plastic cutter won't cut the cardboard, but will make a compression that controls the fold.
Now, if you want to do it right, you'll spend more money, but it's worth it. go to a good lumber yard and buy some 1 x 3's and a sheet of 1/8" plywood called "doorskin". Using the 1x3, build a frame just big enough for the bow and some padding. Cut a rectangle of door skin and nail/glue to the bottom of the frame. Pad the bow and put it in. Screw a top on the box you've built. Pay what it takes to ship it. For a recurve, it will be oversize. so, the bow cost $1000 and it costs $50 to ship it... worth it? You decide.
Here are a couple of pics of a take down bow I just shipped to The Netherlands last week:
Dick in Seattle