I've had 1/2 leg waxes a few times. Gave up on it, because it didn't seem to do the trick for me any better than shaving.
That said, you need to find a beautician who does a lot of waxings, because if you get someone less than proficient, the process can be needlessly painful. You can encounter a beautician who is bad at waxings even at very good salons. So, ask your friends for a referral.
You should check the salon out and make sure it is hygienic and that the beautician is qualified. Then book your appointment.
To be virtually painless (there is stinging), hair removal has to be really fast. After the beautician has treated one area of your leg, she will put her hand on that area--it seems to calm down the stinging. Depending on the beautician and your reaction to the process, the beautician may apply a calming lotion of some kind. Be warned, the area of the leg nearest the ankle is very sensitive, and will likely sting afterwards for a while.