It pays to shop around. Just bought the glass for my wood tank. I contacted several local shops (Syracuse) and, for the same dimensions, same number of pieces, same type of glass, same edge finish, etc. the price fluctuated from $260 to ~$600. Seemingly insignificant differences in edge finish changed the price another $100 - $150. Significant differences in edge finish changed the price almost $200. Changing to low iron glass instead of plain float glass changed the price another few hundred.
So, for what might seem like "similar" glass to a casual observer, the quotes ranged from around $200 to around $1k. For the exact specs I ended up wanting, the price varied from $260 - $600.