you should be able to get about 2 ounces with 600. or pretty damn close. I live in Cali so i couldnt tell you about what quality is out there... If hes the only one you know to buy off of then it doesnt seem like you have much of a choice unless you wait for someone else to come along.

he really shouldnt have a problem with you buying a small amount to test out the weed before buying a couple ounces.