I paid £400 and went to a private dentist for sedation when I needed a number of extractions, the process from my point of view was relatively simple, a quick X-ray was done, a short wait in a waiting room. I was soon horizontal in the chair, without any fuss they had installed a cannula in my right arm and asked me to count to ten, I don't recall going past 7... I was in a fairly sleepy state through the procedure, I recall having a sensation of something happening, like I could feel the teeth being pulled but I was so out of it that it felt pleasant rather than painful. And then I recall waking up slightly and being guided out of the dentist and into a car, you'll need a trusted friend or partner or family member to take you home, I was fairly dozey for the rest of the day, and had the following day off work as a precaution.
They stitched my gums which healed quickly without any problems.