How much does a brand new gearbox cost?

Excuse me, I was wondering if you could shed some light on the cost of a brand new gearbox? I'm in the market for one and would like to have a rough idea of the price range to expect. Could you provide me with an estimate, or perhaps point me in the direction of some reliable sources where I could find this information? I'm interested in getting the best value for my money, so any insights you could offer would be greatly appreciated.