I just picked an '01 300EXC and I had my choice of dealers. I understand there are still 300s "in the warehouse", so most any dealer can get one. I heard of a CA dealer that picked up an order of ten! I think with the popularity of the RFS models many 300s have gone unsold, which is good for those of us that don't want a cam and valve powered dirtbike ;) You should be able to make deals in the mid 5's for an '01, maybe better.
From what I understand, 300's are pretty easy to find right now ( as Montana300 said), with the demand being for the RFS models. My local dealer, Zambon's in Marquette, MI (906-228-7010), just rec'd five 300EXC's and says they're offering awesome deals on them!