How safe and effective is nasal irrigation for treating allergies? is it worth the cost? which method is best?

Very!: It is a great first line treatment for not only allergies but any inflammation of your sinus. As long as you don't use tap water (use distilled water). It is usually very vost effective. Any of the system you find over the counter are good. I like neilmed sinus rinse.

Nasal saline: Nasal saline are safe and effective tools to use. These washes will help remove the inflammatory mediators and reduce the swelling in those with allergies. Are the best medicine for allergies? No but for some patients they are a great non medication alternative that provides some relief.