Your inspector's job is to bring to light any important problems with the house and may also provide you with room to negotiate the price if you can say to the owner, "Well, the home inspector says the roof is in very bad shape. He estimates it's well over seventeen years old, so it's overdue for replacement." Your comments can open negotiating for a lower price and or repairs or replacements.
Call a professional only after your offer has been accepted and you have a signed a sales contract. Make sure there is a clause in your real-estate contract that makes the sale of the home contingent on the inspection. Just make sure you have your inspection done in the timeframe specified in the contract, because if you miss the time allotted, you waive your right to an inspection.
The Cost
Home inspections can cost $150-$500. The price you pay will depend on the part of the country you are in, the size and age of the property, possible optional services (such as septic, well, and radon testing), and the individual inspector's or inspection company's rates. This is a small expense compared with an investment of $100,000 or more.