Most stoves have a clearance in the owners manual that is required to be between the stove and a combustible wall. The fire backs are really only needed if you are going to really try to get the stove out of the way and not adhere to the clearance dimensions. As for a stove cost, the stoves we sell range from 1600-2500 dollars.
You'll be using single wall pipe for the height from the stove to the ceiling which runs around $40 for four feet. In the attic and on the roof you're required to run double wall insulated pipe which is $210 for four feet.
Where you exit your roof is key also, if you are within ten feet of a peak of the house then the pipe must extend at least two feet above the peak or the fire place wont draft correctly. If you are not within ten feet, then the pipe only has to extrude three feet for proper drafting. That can make a huge difference in cost due to having to use double wall pipe. other flashings and caps add about another 150.
One more thing, if the stove is on tile then you do not need a stone pedestal to set the stove on. you will need on if it is on carpet.
So with the prices you should get a rough estimate based on the length of pipe needed. The installation guy we use up here is also a chimney sweep and he averages about 600-1000 for installation.
I hope this helps.
