Ulta Salons (many locations) participates in "Locks of Love", which is an organization that uses your hair to create natural wigs for those who, either have conditions that cause them to prematurely go bald or for those who are on chemotherapy.
My daughter & I, both donated our hair, two years ago. The cut is free but they charge you for styling. They actually give you the cut-ponytail and it is your responsibility to submit it. Other salons also participate in this - just call and ask if they support "Locks of Love".
There is also another organization, that my nephew was involved in, which raises money and funds to cure kid's cancers by supporting cancer research. The name is St. Baldrick's. My nephew is a teacher and the school participated in an event. Since time is of the essence for you, the first choice is the best, however, if you can participate in a St. Baldrick's event or create one of your own...that might be a great choice, too.
http://www.stbaldricks.org/
Good luck.