Found the source of coolant leak on my 1996 BMW 328is- the coolant hose is in need to be replaced.

How much does this cost to have the coolant hose replaced?

That rather depends on which hose is leaking. If the leak is at the radiator end of the top hose, the leak could be from the hose or from a crack in the nipple. In the former case tightening the clamp or replacing the hose will fix it and that's pretty inexpensive. In the latter case the radiator has to be replaced.

also depends on witch hose, one hose is alot more expencive than the other.