1. Buy boots that are the most comfortable for you. I don't think there are boots targeted for "beginners" specifically. It's really just finding the boot that fits your foot best. If you're feet aren't comfy = miserable day of riding. Most boots will fit all bindings.
2. How tall are you? If you're learning, most will tell you to pick up a board that reaches just to your chin. For instance, I'm 5'10" and I ride a 156 - 159. If you're just getting into riding, buying a board is an expense. And if you're traveling to Japan from Australia, you're going to have to get a decent board bag too, which is another expense.
3. Brands? Oh gosh. If you want quality, stick with the name brands. Patagonia. Arcter'yx. North Face. If you don't want to drop the coin on super, top of the line stuff, look at the snowboard-specific brands. Bonfire. Sessions. Volcom. 686. 32. Even so, these brands can get pretty pricey too.
Conservatively, if you're buying all decent gear, you're looking at +/- $1,000 all-in. More if you want nice stuff.