There is a very inexpensive simple effective treatment for Giardiasis.
1. Take any herb containing tannins. This will cause the organisms to detach from the intestinal wall.
Ordinary tea contains tannins, and may be used for treatment of giardiasis. Drink it without milk or sugar, and milk neutralizes the tannins, and Sugar feeds the organisms. There are many other herbs containing tannins. Other examples are Agrimony and Guava leaves. You can look in herbal references for many more.
2. Then eat anything which provides a physical mass to carry them out through the bowel, without providing them with nutrition.
Psyllium can be used. Another option is boiled rice. You can use any bland food to provide a physical mass to carry them out through the bowel. Avoid sugar, fruit, or any food which feeds the organisms.
Giardiasis is a problem in many poor countries. Tea is the most common drink in the world apart from water. Rice is the most common food in the world. Giardiasis can be treated with tea and rice, which is readily available. People just don't know.
I hope you try this, then come back and share your results.