I have never heard of threading but I have been doing electryolsis for several years now on my upper lip and chin. It is painful and expensive over time but as it kills the hair follices, the hair stops growing. I wasn't good about going regularly, as in every week or two and sometimes I did waxing as it removes all the hair. It is also painful, kind of like a pinch, but the pain is only for a second or two.Waxing is not permanent but the hair that grows back becomes lighter and less coarse over time, making electrylsis easier.
I will be looking into laser hair removal for my daughter, not sure about the cost, pain factor, and how long the results are ( I thought it was permanent but someone here said it wasn't for them).
For me, I pay $1 a minute for electrylosis, so costs about $7-8 a session, every 2 weeks. I am now okay to go every 3 weeks, so the cost will be less, but waxing lasts me 4-5 weeks, so I do that every few months.