I'm with 'jb' on this one too. If you had an ASHI-Approved Home Inspector inspect your home, they give Estimates of Repair on your Inspection Report. Ask the background of your Home Inspector. If he's something like a former Architect or General Contractor or Home Builder, he should be able to give you a decent estimate. I, too, wouldn't mess w/this one. What worries most, as with 'jb', is what you can't see.
As an aside, if your Home Inspector is a former Elementary School Teacher, find a qualified inspector! Ask for crudentails of their background. And while you're at it, retain a Real Estate Attorney too. For the peace-of-mind, it's money well-spent! Besides, if you end up buying this home, you MAY need an attorney later on. And if you retain one now, well, you've at least retained one now!
My best to ya and hope this helps.
PS: I'm not a home inspector, nor do I work for one, nor do I work for ASHI, nor am I compensated in ANY way by them or anyone. I am neither a lawer or in the legal or banking business or real estate business, and I'm not compensated by ANY of the aforementioned in any way. (I've been down this road before.) And get an attorney that knows about real estate - And isn't a Divorce Lawyer who will end up 'forwarding' you on to a real estate attorney! And if you want to keep your friends, don't hire them in place of a Home INspector or have them act as your attorney (even if they're qualified.) You may have a 'beef' w/them later on.