How much does crown lengthening cost and does the procedure hurt?

Fees are different in every state and country. I'd suggest you get an estimate from your dentist and if you feel his/her fee is high then get a couple more estimates from dentists your friends see.
As for the procedure hurting, I've personally never had crown lengthening done but I have seen many patients who have. I don't recall any of them mentioning any discomfort/pain but everyone has a different pain threshold. You would be well frozen before the procedure is done and I'm sure some Advil or at worse Tylenol 3's is all you'd need for a day or two after.

Had it done last summer... You can be given a mild sedative to where you are awake, you know what it going on and can communicate with the doctor, but you really don't remember much after the procedure. The thought of the procedure is far worse than having it done. While not something I would sign up for... I wouldn't be overly concerned if I had to do it again... :)

The procedure itself no because there are little or no nerves in the jaw bone. Recovery aches. The ice pack procedure for recovery is very important.

FWIW. Opening the skin on the jaw bone, drilling a big hole and inserting a self-tapping screw for an implant hurts less. In this case the tapping hurts the most.

FWIW: Crown lengthening = jaw bone lowering

Get an estimate... yeah it will be sore for a few days