I recently bought items from several folks on e-bay. Three vendors that stick out for price, helpfulness, cost of and combining shipping and communication were: duck83311, stone clouds, cole5774 (The Wyoming Rock Shop), opalite_one (Oregon Rockshop) and 917jfs. 917jfs stood out in particular. He sends me a message a day or two after completing the transaction saying that he was taking a couple of dollars off the price because he found a crack that wasn't visible or listed in the description. All of these folks were really friendly and helpful. They had great rough and slabs too!
These darn rocks will be my eventual undoing. My wife says I'm obsessed.