In terms of ease, this is a great way to do your bit for someone who has lost their hair due to cancer or alopecia. A quick Internet search can provide you with a number of charities willing to take hair which they send off to make wigs. Some charities specialise in giving wigs to children, some to women with cancer, and some have a mix of recipients. You can choose a charity to match your sentiments as well as your hair. There are a few which will take dyed hair, and some will take shorter hair as well.
Here is a woman who has done some research on a few different charities when she chose to donate her hair a few years back How to choose
It has been a while since I had a haircut, and so I have plenty of hair to donate. This is good, because most charities require at least 8 inches, and most require 10 inches of clean, undyed hair.
Here is one of the charities I am considering donating to:
In the USA you can try:
LocksofLove (my sister grows and donates her hair here every year!)
But there are plenty of places out there!