You are probably thinking of Club Level rooms (non-DVC), which have a Arusha Savannah view. Not sure of the current price, but a standard CL room used to be about $100 more than a Savannah View room
Arusha views were definitely a bookable room in the past. If my memory is correct, it was removed as an option about 4 years ago. The only way now to get a guaranteed Arusha view is to stay Club Level.