The reason it is so cheap is because that is the standard model Burton sends to resorts to use as rentals.
Chances are that the company selling it bought out all of the seasons old rentals from somewhere at a super cheap price. This means that board has been ridden by countless "I have it for the week so who cares what happens to it" types.
It is my strong opinion that if you are going to make the move from renting to owning, that you do it right. Start with some sites like Dogfunk.com or pick up a copy of this sesason's buyer's guide.
Find a board that works perfectly for you and then you can start looking for deals (closeout pricing or slightly used...emphasis on slightly).
Another tip for buying your first setup, start with boots. Spend as much on boots that are perfect on your feet as necessary; this could be the cheapest or most expensive but is definitely the most important purchase you are going to make. This is because it is your feet, not the snowboard, that drive your riding.
Bindings are the second most important followed by the snowboard.
You can expect all of this to cost a reasonable amount of cash, but again if you are going to do it... do it right.