I stalked this item for two years on
Lego.com, TRU,
Amazon, eBay, and until recently the cheapest I ever saw it was when Lego did their 10% off sales (so, $360, plus tax and shipping.) Until recently, thankfully -
I bought it over the summer when TRU did their B1G1 50% off promotion. So, really, I bought two, and spent $600, then sold one on eBay for $400. So the one I'm keeping cost me $200 plus tax (and the eBay/Paypal fees on the one I sold.)
I bought it at 12:01 on the midnight the sale went into effect. I post on a Lego forum (brickset) and read that by 12:15 all the Death Stars were sold out. I don't know if they got more in that week.
This is the last year that it will be in production so I would not wait more than 2-3 more months if it's something you must, must, must have.
Good luck! It looks amazing! Trying to keep it hidden until December but the box is GIGANTIC!