The cheapest reserved tickets for a performance at the Greek Theatre are generally found in Sections 1-3 and 8-10, which make up the side of Bench seating. Getting to and from these seats requires expert climbing of the well-worn and narrow stairs at the Greek. Fans with difficulty walking stairs should avoid these seats on that alone. Others with back issues will be disappointed to learn that these seats do not feature back support.
If you don't have issues with stairs (or like a challenge) and don't mind not having back support, Sections 3 and 8 offer good views at a good elevation over the stage. Sections 1 and 10 should almost be completely avoided as the lighting and sound standards on the stage block the view of the middle of the stage from this angle.