Hello

As usual, my advice on avoiding Kundalini syndrome is to work under the guidance of a qualified guru or yogi. If you must approach Kundalini on your own, be sure that you are ready to surrender your ego to her and live in accordance with her and your Kundalini syndrome will be almost non-existant.
As far as Tummo Reiki is concerned, I don't know where the attunements are free, but I do know that Innersun Reiki (which is taught for free) was developed by a lady who was initiated into gtummo fire by the same teacher as the man who developed Tummo Reiki, so that might be a valid option for you.
If you're interested in controlled Kundalini rise in methods outside of Reiki, there are many sites on the internet that will help. There is a free online course in Yogi Bhajan's Kundalini Yoga on the internet, Nirmala Devi (Sahaja Yoga) offers shaktipat on the internet, there are tons of listings of live Siddha Yoga workshops on the internet, and Mystress Angelique (Fire Serpent Tantra) offers internet shaktipat with a wealth of information on preparing for the experience and then living with Kundalini.
Om Shanti Shanti Shanti,
B.