If you are trying Magnetic Therapy for the first time, you are probably a bit skeptic. Therefore you would not like to start with something too serious, just a trial piece. Bangles are a perfect choice in this case. They are available in many different style and colour, one size (so you cannot mistake to pick the right size) and for a very affordable price.
In a long term, it might be better to buy a chain bracelet, because they are more comfortable if you wear it each and every day.