It is possible. Quite reliable even.
You just have to stick exactly to their rules when making the package. That's quite easy though if you just buy the box and the stripes from the post office.
I sent about 30 kg of stuff from Japan to Finland using the cheapest possible option. It got here in about three months.
And I would call it pricey. I think I paid about 30.000 yet for it..
I can't remember for sure though..