My wife is a Finance Director of a large glass supplier. (They supply trade only) Just to avoid confusion when I mean trade it means they supply to glass fitting companies, glass window frame makers and commerical glaziers etc - not to people who are tradesmen. What she said about the wild pricing is a lot of the product is the same but is priced up on how a company will buy it, how they will pay for it and also how good a customer they are.
In the glass industry its notorious for double glazing companies to go bankrupt and restart.
She says they literally have THOUSANDS of prices for the same stuff. And its all to do with the fact that its a bit of a wild industry.
Effectively there are only really three types of glass
1) Float
2) Laminated
3) Toughend.
Of course its number 3 that you need and the fact you need C-Cuts into it for the hinges (and probably holes for a handle) mean they will probably end up getting the work and doing it. Then they will supply the retailer who will in turn sell it to you. The price will simply reflect how good that retailer has been.
For instance the manufacturer has to take out credit insurance on retailers so that if the retailer goes pop then they can get back some money. But the cost of insurance now is huge. Bottom line is the retailers have to get their glass from somewhere and over the course of this recession the manufacturers have taken BIG hits with bankrupt retailers.
I know its not helping your cause but at least its a "behind the scene" explanation as to why prices for such a basic and cheap material - glass - are so wild.
Also MANY thanks to the wife for supplying Float glass (AKA Plate Glass) which we used to drill through at a recent aquarium and fish tank and REPTILE show to demo tank connectors!
Two holes cut into PLATE GLASS by 365Drills for Tank Connectors for aquariums and reptile tanks!
We do get about dont we !!