I've been a professional camera operator for about 16 years now and also own alot of my own equipment. My 'Average' day rate is 350.00 a day based on an 'average' 10 hour day and they provide the equipment. If I have to travel they cover all expenses, per diem, hotel, etc. If I use my own equipment they pay a daily rental on it plus provide insurance for the wear and tear and possible damage or breakage.
If I shoot for friends or for a discounted rate I won't go less than 200.00 per day.