G'Day Owen,
Welcome to the site!
1. Yes, you should get an entire base set out of a box plus have a small pile of doubles as well.
2. You can usually pick them up off someone on this site for around $90 plus postage. Retail price from a newsagecy would set you back $108.
Just noticed razor77 has listed 3 boxes for sale on this site for $80 plus postage which is a very good price. Link is here if interested ---->
http://www.ozcardtrader.com.au/foru...nrl/74136-3-x-2010-champion-sealed-boxes.html
3. As per 2.