^My guess is $250-300. And that's because the K model has an unlocked multiplier.
On the other hand, it still is a while from now and prices are slowly decreasing. It might hit the $200-250 range.
"Ive just been wondering if it would be a better plan to buy sandy bridge in a a month or two rather then build a system right now? "
Whether or not you choose sandy bridge or the current icores, it will be a better idea to wait because it can only lead to decreased pricing on the current icores. At the very least, the prices won't go up.