Changing my transmission
 

I have a 200 F-250 7.3 L turbo diesel. It has a 4 speed auto. transmision in it. I don't want to get rid of the truck b/c I have invested so much money in it putting a lift on and all. I want a manual transmission and I was wondering if it is possible to change the 4 speed auto to a manual? If so how much money wise am I looking at? Thanks