I'm not really into drifting, but I am addicted to high performance driving schools. If you are planning on having a structured school in a closed, safe environment with qualified instructors, then $150 or even $200 per day would be totally reasonable.
Prospective students need to realize that there are lots of "hidden" costs besides just renting the facility. You need event insurance, equipment (cones, fire extinguishers, etc.), tow truck and ambulance on standby, water truck for skidpad, registration materials (student manuals, etc.), and you may have to pay your instructors. This all adds up. It's unrealistic to expect a well-organized event to cost less than $100-150 per student.
Personally, I would probably be willing to sign up for a nicely organized event just to see what the fuss is about and improve my car control skills. But I would not join in if it were a loosely organized event without good instruction and proper safety measures. I've seen too many cars wrecked at poorly-organized events and I think that hurts the sport.
Emre