Sugar gliders are legal here in Japan. How do I know this? I live in Japan and became a suggie owner about a month ago.
They also have them in pet shops and pet cafes.
So, if you are planning to move here sometime in the future, it might be better to get one here. I know a couple of amazing and kind people that breed them. They also sell them in the pet shops but honestly, the conditions I have seen so far are a bit questionable, even if the pet shop owner was handling them a lot and had a lot of knowledge about them...
Regarding prices, in the pet shops sugar glider prices are the same as abroad (US, Europe etc). But it differs a little bit from breeder to breeder.
They have a lot of places online and offline where you can get everything your suggies need. From HPW dietary needs, to pouches, to toys to snacks.
Let me know if you need anymore info :)