You should get multiple quotes to ensure you know what you're paying for. The Standard, Guardian/Berkshire, Principal, Ameritas/Union Central and Mass Mutual (+/- Ohio National) are those who traditionally have offered true 'own occupation' (meaning if you can't do your job in your specialty, you get benefits, even if you can continue to work in another capacity).
How much it costs depends on how much you insure for, your risk, and a whole host of other things. I pay ~$100/month for ~$4000 in coverage. You can get a plan that covers less with a rider to increase without another exam once you make an attending salary.