I just had one of these done a couple weeks ago, on my new trail horse. It cost $150 and the vet checked his eyes thoroughly, tested his breathing, tried to make him cough by having him breathe into a bag, tested his reflexes, checked his feet carefully, checked his flexion (cramped each hind leg up into an odd position for a couple minutes, then had me walk him briskly away and back to check for a gimp), listened to his heart and lungs and whatever else he listens to inside the horse, and several other things I don't remember right off the bat. It took about an hour and a half. The horse already had a recent Coggins and shots, so no need for those. We debated a blood test for drugs, but it was $300 and the horse did not behave any differently than he did at the seller's (I had him for a week trial period), so neither of us was really concerned about that. The vet said that the level and cost of the test really depends on what you want done, and what you will be using the horse for, like racing, eventing, dressage, trail riding, etc., and it could include radiographs, ultrasound, and all sorts of other things if the owner so chooses. For me, with a light-duty trail horse in very good condition and general health (from the basic exam), we chose not to have more done.