Oh yeah!  Locks of Love!  This organization is the biggie when it comes to providing wigs to kids with alopecia.  They are much beloved by the alopecia and medical hair loss communities, and with very good reason.  Here is a little blurb from their website:

Locks of Love is a non-profit organization that provides hairpieces to financially disadvantaged children under age 18 suffering from long-term medical hair loss. We meet a unique need for children by using donated hair to create the highest quality hair prosthetics. Most of the children helped by Locks of Love have lost their hair due to a medical condition called alopecia areata, which has no known cause or cure. The prostheses we provide help to restore their self-esteem and their confidence, enabling them to face the world and their peers.

Locks of Love was featured in a recent issue of Seventeen Magazine.  You can click on the magazine cover to watch a video of four teens who donated their hair to help kids with alopecia and other forms of medical hairloss.

If you are under 18 and can't afford a good quality hairpiece, you owe it to yourself to consider applying with this wonderful group.