I am in-between batches, currently gearing up for Polarshield v2.0.
You can buy one right now, from The Polargraph Shop, but development is not quite complete and there is already a list of folks with orders in. For this reason, delivery is unlikely to be any earlier than July.
What you need:
The instructable probably gives the best overview of what building and set up is like. Read through it and see if you think you’d be ok with doing it all, because although the kits do contain all the things you need, it isn’t plug-and-play and you will need to do some assembly, and spend some time getting it right. A couple of evenings.
The setting up your PolargraphSD page is the best place to see what comes in the kit, and how to set it up.