A home inspection is always recommended. If you are obtaining a loan, it will be required by your lender. The purpose of the inspection is to give you an idea about the condition of the visible components and major systems of the home. You will be paying for the inspection up-front, but it is the best $400-$500 you'll spend on your home since it gives you a professional's opinion about the condition of the home.
Who does the inspection?
The home inspection will be completed by a Texas-licensed home inspector, trained to identify issues with homes in San Antonio. A good home inspector will take pictures and provide information on all the "issues", ranging from basic cosmetic blemishes to major structural or mechanical problems.
What if there are problems?
Since the inspection is conducted early (during the option period), you'll have the ability to carefully examine the inspection report and to talk to the inspector while you still have the ability to walk away from the contract. Usually, this is not necessary. If there are issues that you need to address, they can often be negotiated with the Seller.