Typically your Home Inspection will alert you to problems in five key areas, and these key areas directly relate to the contract of sale:
1. Foundation: sound and solid
2. Roof free of leaks
3. Plumbing working and leak-free
4. Heating system sufficient and operating
5. Electrical system sufficient and up to code
If there is a serious problem with any of these five items, typically the Seller has a responsibility under the terms of the contract of sale to repair the problem at their expense, not the Purchaser's expense. Sometimes a Purchaser will receive a credit at closing to repair one of these items (assuming the home and the defective issue has not compromised the Lender's appraisal). When the Purchaser receives a credit at closing, the amount of the credit is based upon legitimate estimates for repair and negotiations between the Attorneys representing each party.
Other items you discover are in need of repair/upgrade (i.e. diswasher not operating properly; air conditioner on second floor inoperable, etc.) can be negotiated for a repair credit or replacement at the Seller's expense. Again, these negotiations are handled by the Attorneys.
It is extremely RARE that a purchase price is reduced due to repairs from a Home Inspection. Best to consult with your Attorney for more detailed information in this area.
If you don't already have a good real estate Attorney and you're shopping for homes, you need to reverse your process. First, get properly prequalified for mortgage financing by a Local Mortgage Banker. Second, line up your Attorney. Third, line up your Home Inspector. Fourth, line up a great local Realtor with personal experience in the area in which you'd like to buy.
That's a question for a lawyer to answer. It is also possible to get more information from the NYS Banking dept, which has information hotlines, as this is a common question. Here's a link to more info...