Excited.

After talking about layout and planning last night i'm starting to get excited about how the house will look when its finished.  One of the things I'm really looking forward too is sorting out new windows .  One of my favourite features of the house is the original sash windows, but unfortunately they are in such bad condition there is no way we can keep them.  As our house is in a conservation area we will have to replace them with sash windows. I'm glad about this as I LOVE SASH WINDOWS! but I have a feeling they are going to be very expensive.  
Need a money making plan!  Any ideas?!?