does anyone know any inexpensive ways to strip hair of colours?

Are you trying to remove a hair color mistake? Places like Sally's sell "color oops" which will remove some of the hair color. If you are trying to lighten uncolored hair then the store will have kits for bleaching hair. It's not overly expensive, it is much cheaper than visiting a salon. Be aware that all colour removers are very harsh and drying on the hair and all will leave your hair somewhat dried out. Colour stripper will not return your hair to its original color if your hair color used a peroxide developer or you first bleached your hair before coloring. A colour stripper will not return bleached hair to it original color. It's usually best to visit a salon and have the pros remove or change the color with the least amount of damage. it's more money, but better for your hair.

And do not use household cleansers on your hair. Laundry bleach will burn your scalp and if it gets in your eyes you could damage your sight forever. Other home cleansers are highly corrosive and some are deadly poisonous. Only use products that are designed for use on the hair and scalp.

toilet bleach, paint stripper, white spirit or just do a britany