Real Estate Agent
Keep in mind if you pay the inspector the inspector works for you. Who's to say the seller does not have a "buddy" that is an inspector who will write them a clear letter no matter what.
If the seller has maintained a termite bond on the property the seller can usually request a letter from that company for free. A termite bond is usually transferable so your pretty safe there.
It's best to hire your own. Much like hiring a home inspector.