The money spent could ultimately save you money. If defects are discovered, you'll be in a better position to negotiate with the seller if the defects are documented in a written report. Even if the sellers won't pay to correct defects, you'll benefit by knowing what needs repair. Don't expect the written report to say very much, if anything, about the positive aspects of the property. Also, don't be surprised if the inspection report is loaded with disclaimers.
Inspectors are concerned about their liability.
Sometimes an item the inspector discussed with you at the property takes on a different slant in the written report. If you have any question about such a discrepancy, call the inspector and discuss the matter. Make sure your inspector carries errors and omissions insurance. A few states, like Texas and New Jersey, have licensing requirements for home inspectors.