6 treatments for a partial face (chin, upper lip, sideburns) runs in the $1200 range. After a consultation to see if you qualify for laser hair removal, the doctor/nurse/tech will recommend that you do 6 treatments, 1 every 4-6 weeks. After that you and the tech will assess your progress and decide when you should come in for maintenance.
Laser hair removal does not necessarily kill the hair. It can only be called hair reduction since new hairs can grow and not all the follicles are killed.
The hair grows in 3 stages and the rate from growth to shedding is roughly 6-8 weeks. If anyone tries to tell you to come in more frequently than 4-6 weeks they are bilking you and the treatment won't be effective. Hairs can only be reached by the laser when in the growth phase.
Usually it's just a mild stinging sensation. But, like anything involving pain, different people have different thresholds. Some people prefer to use a numbing cream before treatments, others don't. Personally, I didn't. It hurts less than a tattoo. I've been happy with my results as have most people that I know. The few that have been unhappy have either not responded well to the laser (their hair just wouldn't stop growing) or have been cheated by a laser company.